CS

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Saturday, January 28, 2017

C Language - Overview

C is a general-purpose, high-level language that was originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was originally first implemented on the DEC PDP-11 computer in 1972.

Try it Option Online
We have set up the C Programming environment on-line, so that you can compile and execute all the available examples on line. It gives you confidence in what you are reading and enables you to verify the programs with different options. Feel free to modify any example and execute it on-line.

C - Basic Syntax

You have seen the basic structure of a C program, so it will be easy to understand other basic building blocks of the C programming language.

C - Data Types

Data types in c refer to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

C - Variables

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in C has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

C - Constants & Literals

Constants refer to fixed values that the program may not alter during its execution. These fixed values are also called literals.
Constants can be of any of the basic data types like an integer constant, a floating constant, a character constant, or a string literal. There are enumeration constants as well.
Constants are treated just like regular variables except that their values cannot be modified after their definition.

C - Storage Classes

A storage class defines the scope (visibility) and life-time of variables and/or functions within a C Program. They precede the type that they modify. We have four different storage classes in a C program −

C - Operators

An operator is a symbol that tells the compiler to perform specific mathematical or logical functions. C language is rich in built-in operators and provides the following types of operators −

C - Decision Making

Decision making structures require that the programmer specifies one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.

C - Loops

You may encounter situations, when a block of code needs to be executed several number of times. In general, statements are executed sequentially: The first statement in a function is executed first, followed by the second, and so on.

C - Functions

A function is a group of statements that together perform a task. Every C program has at least one function, which is main(), and all the most trivial programs can define additional functions.
You can divide up your code into separate functions. How you divide up your code among different functions is up to you, but logically the division is such that each function performs a specific task.

C - Scope Rules

A scope in any programming is a region of the program where a defined variable can have its existence and beyond that variable it cannot be accessed. There are three places where variables can be declared in C programming language −

C - Arrays

Arrays a kind of data structure that can store a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.

C - Pointers

Pointers in C are easy and fun to learn. Some C programming tasks are performed more easily with pointers, and other tasks, such as dynamic memory allocation, cannot be performed without using pointers. So it becomes necessary to learn pointers to become a perfect C programmer. Let's start learning them in simple and easy steps.

C - Strings

Strings are actually one-dimensional array of characters terminated by a null character '\0'. Thus a null-terminated string contains the characters that comprise the string followed by a null.
The following declaration and initialization create a string consisting of the word "Hello". To hold the null character at the end of the array, the size of the character array containing the string is one more than the number of characters in the word "Hello."

C - Structures

Arrays allow to define type of variables that can hold several data items of the same kind. Similarly structure is another user defined data type available in C that allows to combine data items of different kinds.

C - Unions

A union is a special data type available in C that allows to store different data types in the same memory location. You can define a union with many members, but only one member can contain a value at any given time. Unions provide an efficient way of using the same memory location for multiple-purpose.

C - Bit Fields

Suppose your C program contains a number of TRUE/FALSE variables grouped in a structure called status, as follows −

struct {
   unsigned int widthValidated;
   unsigned int heightValidated;
} status;

C - typedef

The C programming language provides a keyword called typedef, which you can use to give a type, a new name. Following is an example to define a term BYTE for one-byte numbers −

typedef unsigned char BYTE;

C - Input & Output

When we say Input, it means to feed some data into a program. An input can be given in the form of a file or from the command line. C programming provides a set of built-in functions to read the given input and feed it to the program as per requirement.

C - File I/O

The last chapter explained the standard input and output devices handled by C programming language. This chapter cover how C programmers can create, open, close text or binary files for their data storage.
A file represents a sequence of bytes, regardless of it being a text file or a binary file.

C - Preprocessors

The C Preprocessor is not a part of the compiler, but is a separate step in the compilation process. In simple terms, a C Preprocessor is just a text substitution tool and it instructs the compiler to do required pre-processing before the actual compilation. We'll refer to the C Preprocessor as CPP.

C - Header Files

A header file is a file with extension .h which contains C function declarations and macro definitions to be shared between several source files. There are two types of header files: the files that the programmer writes and the files that comes with your compiler.

C - Type Casting

Type casting is a way to convert a variable from one data type to another data type. For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. You can convert the values from one type to another explicitly using the cast operator as follows −

(type_name) expression

C - Error Handling

As such, C programming does not provide direct support for error handling but being a system programming language, it provides you access at lower level in the form of return values. Most of the C or even Unix function calls return -1 or NULL in case of any error and set an error code errno. It is set as a global variable and indicates an error occurred during any function call. You can find various error codes defined in <error.h> header file.

C - Recursion

Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

void recursion() {
   recursion(); /* function calls itself */

C - Variable Arguments

Sometimes, you may come across a situation, when you want to have a function, which can take variable number of arguments, i.e., parameters, instead of predefined number of parameters. The C programming language provides a solution for this situation and you are allowed to define a function which can accept variable number of parameters based on your requirement.

C - Memory Management

This chapter explains dynamic memory management in C. The C programming language provides several functions for memory allocation and management. These functions can be found in the <stdlib.h> header file.

C - Command Line Arguments

It is possible to pass some values from the command line to your C programs when they are executed. These values are called command line arguments and many times they are important for your program especially when you want to control your program from outside instead of hard coding those values inside the code.

C Programming Questions and Answers

C Programming Questions and Answers has been designed with a special intention of helping students and professionals preparing for various Certification Exams and Job Interviews. This section provides a useful collection of sample Interview Questions and Multiple Choice Questions (MCQs) and their answers with appropriate explanations.

C - Language Overview

C - Useful Resources

The following resources contain additional information on C. Please use them to get more in-depth knowledge on this topic.

Discuss C

C is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis M. Ritchie at the Bell Telephone Laboratories to develop the UNIX operating system. C is the most widely used computer language. It keeps fluctuating at number one scale of popularity along with Java programming language, which is also equally popular and most widely used among modern software programmers.

C++ Library -

Introduction

This data type represents the file stream generally, and has the capabilities of both ofstream and ifstream which means it can create files, write information to files, and read information from files.

Introduction

iomanip is a library that is used to manipulate the output of C++ program. Using C++, header providing parametric manipulators as shown below −

Introduction

The C++ standard libraries provide an extensive set of input/output capabilities which we will see in subsequent chapters. This chapter will discuss very basic and most common I/O operations required for C++ programming.
Input-Output base classes and types for the IOStream hierarchy of classes as shown below −

Description

It is used to input-Output forward declarations,this header provides forward declarations for the types of the standard input/output library.

Description

It is used in standard Input / Output Streams Library.

Declaration

Following is the declaration for iosstream function.

Description

The Istream used for header providing the standard input and combined input/output stream classes.

Class templates

Introduction

It is an output stream objects can write sequences of characters and represent other kinds of data. Specific members are provided to perform these output operations.

Introduction

It is a string stream for header.

Class Templates

Following are the Class Templates for sstram.

S.N.	Class Templates	Definition
1	basic_istringstream	It is an input string stream
2	basic_ostringstream	It is an output string stream
3	basic_stringstream	It is a basic string steam
4	basic_stringbuf	It is a string stream buffer

Introduction

It is a stream buffer and it is to be used in combination with input/output streams.

Class templates

S.N.	Class	Definition
1	basic_streambuf	It is a basic stream buffer
2	wstreambuf	It is used in base buffer class in stream

Introduction

These are types that encapsulate a value whose access is guaranteed to not cause data races and can be used to synchronize memory accesses among different threads and he atomic library provides components for fine-grained atomic operations allowing for lockless concurrent programming. Each atomic operation is indivisible with regards to any other atomic operation that involves the same object.

Introduction

It implements the complex class to contain complex numbers in cartesian form and several functions and overloads to operate with them.

Introduction

It is a standard exception class. All objects thrown by components of the standard library are derived from this class. Therefore, all standard exceptions can be caught by catching this type by reference.

Introduction

Function objects are objects specifically designed to be used with a syntax similar to that of functions. Instances of std::function can store, copy, and invoke any Callable target -- functions, lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers to data members.

Introduction

It is a Numeric limits type and it provides information about the properties of arithmetic types (either integral or floating-point) in the specific platform for which the library compiles.

Introduction

It is a localization library and a set of features that are culture-specific, which can be used by programs to be more portable internationally.

Introduction

It defines general utilities to manage dynamic memory in header.

Allocators

S.N.	Allocator & description
1	allocator It is a default allocator.

Introduction

It is a header describes functions used to manage dynamic storage in C++.The header also defines some specific types and the set_new_handler / get_new_handler pair of functions as shown below −

Introduction

It is used to generalized numeric operations and this header describes a set of algorithms to perform certain operations on sequences of numeric values. In C++, It includes common mathematical functions and types, as well as optimized numeric arrays and support for random number generation.

Introduction

It is a standardized way to express patterns to be matched against sequences of characters. some of typical regex parameters are as shown below −

Introduction

It is an exception classes and this header defines a set of standard exceptions that both the library and programs can use to report common errors.

Introduction

String is a class and all objects that in string represent sequences of characters.

Declaration

Following is the declaration for std::string.

typedef basic_string<char> string;

Introduction

Thread is a sequence of instructions that can be executed concurrently with other such sequences in multithreading environments, while sharing a same address spac.

Introduction

These are objects that pack elements of -possibly- different types together in a single object, just like pair objects do for pairs of elements, but generalized for any number of elements. It is closely related to the pair class (defined in header ): Tuples can be constructed from pairs, and pairs can be treated as tuples for certain purposes.

Introduction

It defines in header and related to operators typeid and dynamic_cast.

Declaration

Following is the declaration for std::type_info.

class type_info;

Introduction

It contains utilities in unrelated domains.

Pairs − these objects can hold two values of different types: pair, make_pair, piecewise_construct, piecewise_construct_t.

Introduction

It is a library for arrays of numeric values and this header declares the valarray class and its auxiliary classes and functions.

Introduction

Arrays are sequence container of fixed size. Container is a objects that holds data of same type. Sequence containers store elements strictly in linear sequence.

Introduction

Bitset represents a fixed-size sequence of N bits and stores values either 0 or 1. Zero means value is false or bit is unset and one means value is true or bit is set. Bitset class emulates space efficient array of boolean values, where each element occupies only one bit.

Introduction

Deque is acronym for Double Ended Queue. It is a sequence container that can change it's size runtime. Container is an object that holds data of same type. Sequence containers store elements strictly in linear sequence.

Introduction

forward_list is a popularly used sequence container. Container is an object that holds data of same type. forward_list container is implemented as singly linked-list, hence it provides unidirectional sequential access to it's data.

Introduction

List is a popularly used sequence container. Container is an object that holds data of same type. List container is implemented as doubly linked-list, hence it provides bidirectional sequential access to it's data.
List doesn't provide fast random access, it only supports sequential access in both directions. List allows insertion and deletion operation anywhere within a sequence in constant time.

Introduction to queue

Queue is a data structure designed to operate in FIFO (First in First out) context. In queue elements are inserted from rear end and get removed from front end.
Queue class is container adapter. Container is an objects that hold data of same type. Queue can be created from different sequence containers.

Introduction

A set is an Associative container which contains a sorted set of unique objects of type Key. Each element may occur only once, so duplicates are not allowed.
There are four kind of Associative containers: set, multiset, map and multimap.

Introduction

Stack is a data structure designed to operate in LIFO (Last in First out) context. In stack elements are inserted as well as get removed from only one end.
Stack class is container adapter. Container is an objects that hold data of same type. Stack can be created from different sequence containers.

Introduction to unordered_map

Unordered map is dictionary like data structure. It is a sequence of (key, value) pair, where only single value is associated with each unique key. It is often referred as associative array. It enables fast retrieval of individual elements based on their keys.

Introduction

It is an associative container that store unique elements in no particular order, and which allow for fast retrieval of individual elements based on their value.

Introduction to algorithm

The algorithm library provides several functions that can be used for a variety of purposes, for instance searching, sorting, counting, manipulating and so on. These functions operate on ranges of elements and the range is defined as [first, last).

C++ - Overview

C++ is a statically typed, compiled, general-purpose, case-sensitive, free-form programming language that supports procedural, object-oriented, and generic programming.
C++ is regarded as a middle-level language, as it comprises a combination of both high-level and low-level language features.

Try it Option Online
You really do not need to set up your own environment to start learning C++ programming language. Reason is very simple, we already have set up C++ Programming environment online, so that you can compile and execute all the available examples online at the same time when you are doing your theory work.

C++ Basic Syntax

When we consider a C++ program, it can be defined as a collection of objects that communicate via invoking each other's methods. Let us now briefly look into what do class, object, methods and Instance variables mean.

Comments in C++

Program comments are explanatory statements that you can include in the C++ code that you write and helps anyone reading it's source code. All programming languages allow for some form of comments.
C++ supports single-line and multi-line comments. All characters available inside any comment are ignored by C++ compiler.

C++ Data Types

While doing programming in any programming language, you need to use various variables to store various information. Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in memory.

Variable Scope in C++

A scope is a region of the program and broadly speaking there are three places, where variables can be declared −

Inside a function or a block which is called local variables,
In the definition of function parameters which is called formal parameters.
Outside of all functions which is called global variables.

C++ Constants/Literals

Constants refer to fixed values that the program may not alter and they are called literals.
Constants can be of any of the basic data types and can be divided into Integer Numerals, Floating-Point Numerals, Characters, Strings and Boolean Values.

C++ Modifier Types

C++ allows the char, int, and double data types to have modifiers preceding them. A modifier is used to alter the meaning of the base type so that it more precisely fits the needs of various situations.
The data type modifiers are listed here:

Storage Classes in C++

A storage class defines the scope (visibility) and life-time of variables and/or functions within a C++ Program. These specifiers precede the type that they modify. There are following storage classes, which can be used in a C++ Program

Operators in C++

An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. C++ is rich in built-in operators and provides the following types of operators:

C++ Loop Types

There may be a situation, when you need to execute a block of code several number of times. In general statements are executed sequentially: The first statement in a function is executed first, followed by the second, and so on.

C++ decision making statements

Decision making structures require that the programmer specify one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.

C++ Functions

A function is a group of statements that together perform a task. Every C++ program has at least one function, which is main(), and all the most trivial programs can define additional functions.
You can divide up your code into separate functions. How you divide up your code among different functions is up to you, but logically the division usually is so each function performs a specific task.

Numbers in C++

Normally, when we work with Numbers, we use primitive data types such as int, short, long, float and double, etc. The number data types, their possible values and number ranges have been explained while discussing C++ Data Types.

C++ Arrays

C++ provides a data structure, the array, which stores a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.

C++ Strings

C++ provides following two types of string representations:

The C-style character string.
The string class type introduced with Standard C++.

C++ Pointers

C++ pointers are easy and fun to learn. Some C++ tasks are performed more easily with pointers, and other C++ tasks, such as dynamic memory allocation, cannot be performed without them.
As you know every variable is a memory location and every memory location has its address defined which can be accessed using ampersand (&) operator which denotes an address in memory.

C++ References

A reference variable is an alias, that is, another name for an already existing variable. Once a reference is initialized with a variable, either the variable name or the reference name may be used to refer to the variable.

C++ Date and Time

The C++ standard library does not provide a proper date type. C++ inherits the structs and functions for date and time manipulation from C. To access date and time related functions and structures, you would need to include <ctime> header file in your C++ program.

C++ Basic Input/Output

C++ Data Structures

C/C++ arrays allow you to define variables that combine several data items of the same kind but structure is another user defined data type which allows you to combine data items of different kinds.
Structures are used to represent a record, suppose you want to keep track of your books in a library. You might want to track the following attributes about each book:

C++ Classes and Objects

The main purpose of C++ programming is to add object orientation to the C programming language and classes are the central feature of C++ that supports object-oriented programming and are often called user-defined types.

C++ Inheritance

One of the most important concepts in object-oriented programming is that of inheritance. Inheritance allows us to define a class in terms of another class, which makes it easier to create and maintain an application. This also provides an opportunity to reuse the code functionality and fast implementation time.

C++ Overloading (Operator and Function)

C++ allows you to specify more than one definition for a function name or an operator in the same scope, which is called function overloading and operator overloading respectively.

Polymorphism in C++

The word polymorphism means having many forms. Typically, polymorphism occurs when there is a hierarchy of classes and they are related by inheritance.
C++ polymorphism means that a call to a member function will cause a different function to be executed depending on the type of object that invokes the function.

Data Abstraction in C++

Data abstraction refers to, providing only essential information to the outside world and hiding their background details, i.e., to represent the needed information in program without presenting the details.
Data abstraction is a programming (and design) technique that relies on the separation of interface and implementation.

Data Encapsulation in C++

All C++ programs are composed of the following two fundamental elements:

Program statements (code): This is the part of a program that performs actions and they are called functions.
Program data: The data is the information of the program which affected by the program functions.

Interfaces in C++ (Abstract Classes)

An interface describes the behavior or capabilities of a C++ class without committing to a particular implementation of that class.
The C++ interfaces are implemented using abstract classes and these abstract classes should not be confused with data abstraction which is a concept of keeping implementation details separate from associated data.

C++ Files and Streams

So far, we have been using the iostream standard library, which provides cin and cout methods for reading from standard input and writing to standard output respectively.
This tutorial will teach you how to read and write from a file. This requires another standard C++ library called fstream, which defines three new data types:

C++ Exception Handling

An exception is a problem that arises during the execution of a program. A C++ exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero.
Exceptions provide a way to transfer control from one part of a program to another. C++ exception handling is built upon three keywords: try, catch, and throw.

C++ Dynamic Memory

A good understanding of how dynamic memory really works in C++ is essential to becoming a good C++ programmer. Memory in your C++ program is divided into two parts:

The stack: All variables declared inside the function will take up memory from the stack.
The heap: This is unused memory of the program and can be used to allocate the memory dynamically when program runs.

Namespaces in C++

Consider a situation, when we have two persons with the same name, Zara, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area if they live in different area or their mother or father name, etc.

C++ Templates

Templates are the foundation of generic programming, which involves writing code in a way that is independent of any particular type.
A template is a blueprint or formula for creating a generic class or a function. The library containers like iterators and algorithms are examples of generic programming and have been developed using template concept.

C++ Preprocessor

The preprocessors are the directives, which give instruction to the compiler to preprocess the information before actual compilation starts.
All preprocessor directives begin with #, and only white-space characters may appear before a preprocessor directive on a line. Preprocessor directives are not C++ statements, so they do not end in a semicolon (;).

C++ Signal Handling

Signals are the interrupts delivered to a process by the operating system which can terminate a program prematurely. You can generate interrupts by pressing Ctrl+C on a UNIX, LINUX, Mac OS X or Windows system.

C++ Multithreading

Multithreading is a specialized form of multitasking and a multitasking is the feature that allows your computer to run two or more programs concurrently. In general, there are two types of multitasking: process-based and thread-based.

What is CGI?

The Common Gateway Interface, or CGI, is a set of standards that define how information is exchanged between the web server and a custom script.
The CGI specs are currently maintained by the NCSA and NCSA defines CGI is as follows:
The Common Gateway Interface, or CGI, is a standard for external gateway programs to interface with information servers such as HTTP servers.
The current version is CGI/1.1 and CGI/1.2 is under progress.

C++ Questions and Answers

C++ Questions and Answers has been designed with a special intention of helping students and professionals preparing for various Certification Exams and Job Interviews. This section provides a useful collection of sample Interview Questions and Multiple Choice Questions (MCQs) and their answers with appropriate explanations.

C++ Quick Guide

C++ Object Oriented

The prime purpose of C++ programming was to add object orientation to the C programming language, which is in itself one of the most powerful programming languages.
The core of the pure object-oriented programming is to create an object, in code, that has certain properties and methods.

C++ STL Tutorial

Hope you already understand the concept of C++ Template which we already have discussed in one of the chapters. The C++ STL (Standard Template Library) is a powerful set of C++ template classes to provides general-purpose templatized classes and functions that implement many popular and commonly used algorithms and data structures like vectors, lists, queues, and stacks.

C++ Standard Library

The C++ Standard Library can be categorized into two parts:

The Standard Function Library: This library consists of general-purpose,stand-alone functions that are not part of any class. The function library is inherited from C.
The Object Oriented Class Library: This is a collection of classes and associated functions.

C++ Useful Resources

The following resources contain additional information on C++. Please use them to get more in-depth knowledge on this topic.

Discuss C++

C++ is a middle-level programming language developed by Bjarne Stroustrup starting in 1979 at Bell Labs. C++ runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. This reference will take you through simple and practical approach while learning C++ Programming language.

Introduction to Computer Program

Before getting into computer programming, let us first understand computer programs and what they do.

A computer program is a sequence of instructions written using a Computer Programming Language to perform a specified task by the computer.

The two important terms that we have used in the above definition are −

Computer Programming - Basics

We assume you are well aware of English Language, which is a well-known Human Interface Language. English has a predefined grammar, which needs to be followed to write English statements in a correct way. Likewise, most of the Human Interface Languages (Hindi, English, Spanish, French, etc.) are made of several elements like verbs, nouns, adjectives, adverbs, propositions, and conjunctions, etc.

Computer Programming - Environment

Though Environment Setup is not an element of any Programming Language, it is the first step to be followed before setting on to write a program.
When we say Environment Setup, it simply implies a base on top of which we can do our programming. Thus, we need to have the required software setup, i.e., installation on our PC which will be used to write computer programs, compile, and execute them.

Computer Programming - Basic Syntax

Let’s start with a little coding, which will really make you a computer programmer. We are going to write a single-line computer program to write Hello, World! on your screen. Let’s see how it can be written using different programming languages.

Computer Programming - Data Types

Let's discuss about a very simple but very important concept available in almost all the programming languages which is called data types. As its name indicates, a data type represents a type of the data which you can process using your computer program. It can be numeric, alphanumeric, decimal, etc.

Computer Programming - Variables

Variables are the names you give to computer memory locations which are used to store values in a computer program.
For example, assume you want to store two values 10 and 20 in your program and at a later stage, you want to use these two values. Let's see how you will do it. Here are the following three simple steps −

Computer Programming - Keywords

So far, we have covered two important concepts called variables and their data types. We discussed how to use int, long, and float to specify different data types. We also learnt how to name the variables to store different values.

Computer Programming - Operators

An operator in a programming language is a symbol that tells the compiler or interpreter to perform specific mathematical, relational or logical operation and produce final result. This chapter will explain the concept of operators and it will take you through the important arithmetic and relational operators available in C, Java, and Python.

Computer Programming - Decision

Decision making is critical to computer programming. There will be many situations when you will be given two or more options and you will have to select an option based on the given conditions. For example, we want to print a remark about a student based on his secured marks. Following is the situation −

Computer Programming - Loops

Let's consider a situation when you want to print Hello, World! five times. Here is a simple C program to do the same −

#include <stdio.h>

main() {

Computer Programming - Numbers

Every programming language provides support for manipulating different types of numbers such as simple whole integers and floating point numbers. C, Java, and Python categorize these numbers in several categories based on their nature.

Computer Programming - Characters

If it was easy to work with numbers in computer programming, it would be even easier to work with characters. Characters are simple alphabets like a, b, c, d...., A, B, C, D,....., but with an exception. In computer programming, any single digit number like 0, 1, 2,....and special characters like $, %, +, -.... etc., are also treated as characters and to assign them in a character type variable, you simply need to put them inside single quotes.

Computer Programming - Arrays

Consider a situation where we need to store five integer numbers. If we use programming's simple variable and data type concepts, then we need five variables of int data type and the program will be as follows −

#include <stdio.h>

Computer Programming - Strings

During our discussion about characters, we learnt that character data type deals with a single character and you can assign any character from your keyboard to a character type variable.

Computer Programming - Functions

A function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing. You have already seen various functions like printf() and main().

Computer Files

A computer file is used to store data in digital format like plain text, image data, or any other content. Computer files can be organized inside different directories. Files are used to keep digital data, whereas directories are used to keep files.

Computer Programming - Summary

We appreciate your patience for going through this tutorial. We have tried to keep it concise but as this subject contains several topics, we have shown a few examples in detail.

Computer Programming - Overview

Introduction to Computer Program

Before getting into computer programming, let us first understand computer programs and what they do.

A computer program is a sequence of instructions written using a Computer Programming Language to perform a specified task by the computer.

The two important terms that we have used in the above definition are −

Computer Programming - Useful Resources

The following resources contain additional information on Computer Programming. Please use them to get more in-depth knowledge on this topic.

Discuss Computer Programming

Computer programming is the act of writing computer programs, which are a sequence of instructions written using a Computer Programming Language to perform a specified task by the computer.

COBOL - Overview

COBOL is a high-level language. One must understand the way COBOL works. Computers only understand machine code, a binary stream of 0s and 1s. COBOL code must be converted into machine code using a compiler.

Try it Option Online
We have set up the COBOL Programming environment online, so that you can compile and execute all the available examples online. It gives you confidence in what you are reading and enables you to verify the programs with different options. Feel free to modify any example and execute it online.

COBOL - Program Structure

A COBOL program structure consists of divisions as shown in the following image:

A brief introduction of these divisions is given below:

Character Set

'Characters' are lowest in the hierarchy and they cannot be divided further. The COBOL Character Set includes 78 characters which are shown below:

COBOL - Data Types

Data Division is used to define the variables used in a program. To describe data in COBOL, one must understand the following terms:

Data Name
Level Number
Picture Clause
Value Clause

COBOL - Basic Verbs

COBOL verbs are used in the procedure division for data processing. A statement always start with a COBOL verb. There are several COBOL verbs with different types of actions.

COBOL - Data Layout

COBOL layout is the description of use of each field and the values present in it. Following are the data description entries used in COBOL:

Redefines Clause
Renames Clause
Usage Clause
Copybooks

COBOL - Condition Statements

Conditional statements are used to change the execution flow depending on certain conditions specified by the programmer. Conditional statements will always evaluate to true or false. Conditions are used in IF, Evaluate and Perform statements. The different types of conditions are as follows:

COBOL - Loop Statements

There are some tasks that need to be done over and over again like reading each record of a file till its end. The loop statements used in COBOL are:

Perform Thru
Perform Until
Perform Times
Perform Varying

COBOL - String Handling

String handling statements in COBOL are used to do multiple functional operations on strings. Following are the string handling statements:

Inspect
String
Unstring

COBOL - Table Processing

Arrays in COBOL are known as tables. An array is a linear data structure and is collection of individual data items of same type. Data items of a table are internally sorted.

COBOL - File Handling

The concept of files in COBOL is different from that in C/C++. While learning the basics of 'File' in COBOL, the concepts of both languages should not be co-related. Simple text files cannot be used in COBOL, instead PS (Physical Sequential) and VSAM files are used. PS files will be discussed in this module.

COBOL - File Organization

File organization indicates how the records are organized in a file. There are different types of organizations for files so as to increase their efficiency of accessing the records. Following are the types of file organization schemes:

COBOL - File Access Mode

Till now, file organization schemes have been discussed. For each file organization scheme, different access modes can be used. Following are the types of file access modes:

Sequential Access
Random Access
Dynamic Access

COBOL - File Handling Verbs

File handling verbs are used to perform various operations on files. Following are the file handling verbs:

Open
Read
Write
Rewrite
Delete
Start
Close

COBOL - Subroutines

Cobol subroutine is a program that can be compiled independently but cannot be executed independently. There are two types of subroutines: internal subroutines like Perform statements and external subroutines like CALL verb.

COBOL - Internal Sort

Sorting of data in a file or merging of two or more files is a common necessity in almost all business-oriented applications. Sorting is used for arranging records either in ascending or descending order, so that sequential processing can be performed. There are two techniques which are used for sorting files in COBOL:

COBOL - Database Interface

As of now, we have learnt the use of files in COBOL. Now, we will discuss how a COBOL program interacts with DB2. It involves the following terms:

Embedded SQL
DB2 Application Programming
Host Variables
SQLCA
SQL Queries
Cursors

COBOL Interview Questions

Dear readers, these COBOL Interview Questions have been designed especially to get you acquainted with the nature of questions you may encounter during your interview for the subject of COBOL Programming Language. As per my experience, good interviewers hardly plan to ask any particular question during your interview.

COBOL Questions and Answers

COBOL Questions and Answers has been designed with a special intention of helping students and professionals preparing for various Certification Exams and Job Interviews. This section provides a useful collection of sample Interview Questions and Multiple Choice Questions (MCQs) and their answers with appropriate explanations.

COBOL - Overview

Introduction to COBOL

COBOL - Useful Resources

The following resources contain additional information on COBOL. Please use them to get more in-depth knowledge on this topic.

Discuss COBOL

COBOL stands for Common Business Oriented Language.The US Department of Defense, in a conference, formed CODASYL (Conference on Data Systems Language) to develop a language for business data processing needs which is now known as COBOL.

Clojure - Overview

Clojure is a high level, dynamic functional programming language. Clojure is designed based on the LISP programming language and has compilers which makes it run on both Java and .Net runtime environment.
Before we talk about Clojure, let’s just have a quick description of LISP programming language.

Try it Option Online
We have set up the Clojure Programming environment on-line, so that you can compile and execute all the available examples on line. It gives you confidence in what you are reading and enables you to verify the programs with different options. Feel free to modify any example and execute it on-line.

Clojure - Basic Syntax

In order to understand the basic syntax of Clojure, let’s first look at a simple Hello World program.

Hello World as a Complete Program

Write ‘Hello world’ in a complete Clojure program. Following is an example.

Clojure - REPL

REPL (read-eval-print loop) is a tool for experimenting with Clojure code. It allows you to interact with a running program and quickly try out if things work out as they should. It does this by presenting you with a prompt where you can enter the code. It then reads your input, evaluates it, prints the result, and loops, presenting you with a prompt again.

Clojure - Data Types

Clojure offers a wide variety of built-in data types.

Built-in Data Types

Following is a list of data types which are defined in Clojure.

Integers − Following are the representation of Integers available in Clojure.
- Decimal Integers (Short, Long and Int) − These are used to represent whole numbers. For example, 1234.

Clojure - Variables

In Clojure, variables are defined by the ‘def’ keyword. It’s a bit different wherein the concept of variables has more to do with binding. In Clojure, a value is bound to a variable. One key thing to note in Clojure is that variables are immutable, which means that in order for the value of the variable to change, it needs to be destroyed and recreated again.

Clojure - Operators

An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations.
Clojure has the following types of operators −

Arithmetic operators
Relational operators
Logical operators
Bitwise operators

Clojure - Loops

So far we have seen statements which are executed one after the other in a sequential manner. Additionally, statements are provided in Clojure to alter the flow of control in a program’s logic. They are then classified into flow of control statements which we will see in detail.

Clojure - Decision Making

Decision-making structures require that the programmer specify one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.

Clojure - Functions

Clojure is known as a functional programming language, hence you would expect to see a lot of emphasis on how functions work in Clojure. This chapter covers what all can be done with functions in Clojure.

Clojure - Numbers

Numbers datatype in Clojure is derived from Java classes.
Clojure supports integer and floating point numbers.

An integer is a value that does not include a fraction.
A floating-point number is a decimal value that includes a decimal fraction.

Clojure - Recursion

We have seen the recur statement in an earlier topic and whereas the ‘for’ loop is somewhat like a loop, recur is a real loop in Clojure.

Clojure - File I/O

Clojure provides a number of helper methods when working with I/O. It offers easier classes to provide the following functionalities for files.

Reading files
Writing to files
Seeing whether a file is a file or directory

Clojure - Strings

A String literal is constructed in Clojure by enclosing the string text in quotations. Strings in Clojure need to be constructed using the double quotation marks such as “Hello World”.

Clojure - Lists

List is a structure used to store a collection of data items. In Clojure, the List implements the ISeq interface. Lists are created in Clojure by using the list function.

Clojure - Sets

Sets in Clojure are a set of unique values. Sets are created in Clojure with the help of the set command.

Example

Following is an example of the creation of sets in Clojure.

(ns clojure.examples.example
   (:gen-class))

Clojure - Vectors

A Vector is a collection of values indexed by contiguous integers. A vector is created by using the vector method in Clojure.

Clojure - Maps

A Map is a collection that maps keys to values. Two different map types are provided - hashed and sorted. HashMaps require keys that correctly support hashCode and equals. SortedMaps require keys that implement Comparable, or an instance of Comparator.

Clojure - Namespaces

Namespaces in Clojure are used to differentiate classes into separate logical spaces just like in Java. Consider the following statement.

(:require [clojure.set :as set])

Clojure - Exception Handling

Exception handling is required in any programming language to handle the runtime errors so that the normal flow of the application can be maintained. Exception usually disrupts the normal flow of the application, which is the reason why we need to use exception handling in our application.

Clojure - Sequences

Sequences are created with the help of the ‘seq’ command. Following is a simple example of a sequence creation.

(ns clojure.examples.example
   (:gen-class))

Clojure - Regular Expressions

A regular expression is a pattern that is used to find substrings in text. Regular expressions are used in a variety of programming languages and used a lot in LISP type programming languages.
Following is an example of a regular expression.

Clojure - Predicates

Predicates are functions that evaluate a condition and provide a value of either true or false. We have seen predicate functions in the examples of the chapter on numbers. We have seen functions like ‘even?’ which is used to test if a number is even or not, or ‘neg?’ which is used to test if a number is greater than zero or not.

Clojure - Destructuring

Destructuring is a functionality within Clojure, which allows one to extract values from a data structure, such as a vector and bind them to symbols without having to explicitly traverse the datastructure.
Let’s look at an example of what exactly Destructuring means and how does it happen.

Clojure - Date and Time

Since the Clojure framework is derived from Java classes, one can use the date-time classes available in Java in Clojure. The class date represents a specific instant in time, with millisecond precision.
Following are the methods available for the date-time class.

Clojure - Atoms

Atoms are a data type in Clojure that provide a way to manage shared, synchronous, independent state. An atom is just like any reference type in any other programming language. The primary use of an atom is to hold Clojure’s immutable datastructures. The value held by an atom is changed with the swap! method.

Clojure - Metadata

In Clojure, metadata is used to annotate the data in a collection or for the data stored in a symbol. This is normally used to annotate data about types to the underlying compiler, but can also be used for developers.

Clojure - StructMaps

StructMaps are used for creating structures in Clojure. For example, if you wanted to create a structure which comprised of an Employee Name and Employeeid, you can do that with StructMaps.
The following operations are possible in Clojure with regards to StructMaps.

Clojure - Agents

As pointed out many times, Clojure is a programming language wherein many of the data types are immutable, which means that the only way one can change the value of a variable is to create a new variable and assign the new value to it. However, Clojure does provide some elements, which can create an mutable state.

Clojure - Watchers

Watchers are functions added to variable types such as atoms and reference variables which get invoked when a value of the variable type changes. For example, if the calling program changes the value of an atom variable, and if a watcher function is attached to the atom variable, the function will be invoked as soon as the value of the atom is changed.

Clojure - Macros

In any language, Macros are used to generate inline code. Clojure is no exception and provides simple macro facilities for developers. Macros are used to write code-generation routines, which provide the developer a powerful way to tailor the language to the needs of the developer.

Clojure - Reference Values

Reference values are another way Clojure can work with the demand to have mutable variables. Clojure provides mutable data types such as atoms, agents, and reference types.
Following are the operations available for reference values.

Clojure - Databases

In order to use the database functionality, please ensure to first download the jdbc files from the following url − https://codeload.github.com/clojure/java.jdbc/zip/master
You will find a zip file which has the necessary drivers for Clojure to have the ability to connect to databases. Once the zip file is extracted, ensure to add the unzipped location to your classpath.

Clojure - Java Interface

As we already know, Clojure code runs on the Java virtual environment at the end. Thus it only makes sense that Clojure is able to utilize all of the functionalities from Java. In this chapter, let’s discuss the correlation between Clojure and Java.

Clojure - Concurrent Programming

In Clojure programming most data types are immutable, thus when it comes to concurrent programming, the code using these data types are pretty safe when the code runs on multiple processors. But many a times, there is a requirement to share data, and when it comes to shared data across multiple processors, it becomes necessary to ensure that the state of the data is maintained in terms of integrity when working with multiple processors. This is known as

Clojure - Applications

Clojure has some contributed libraries which have the enablement for creating Desktop and Web-based applications. Let’s discuss each one of them.

Clojure - Automated Testing

In this chapter, let’s discuss automated testing options provided by Clojure.

Testing for Client Applications

In order to use testing for Clojure framework, you have to use the dependencies located at https://github.com/slagyr/speclj#manual-installation

Clojure - Libraries

One thing which makes the Clojure library so powerful is the number of libraries available for the Clojure framework. We have already seen so many libraries used in our earlier examples for web testing, web development, developing swing-based applications, the jdbc library for connecting to MySQL databases. Following are just a couple of examples of few more libraries.

Clojure - Overview

Clojure - Useful Resources

The following resources contain additional information on Clojure. Please use them to get more in-depth knowledge on this.

Discuss Clojure

Clojure is a high level, dynamic functional programming language. It is designed, based on the LISP programming language, and has compilers that makes it possible to be run on both Java and .Net runtime environment. This tutorial is fairly comprehensive and covers various functions involved in Clojure. All the functions are explained using examples for easy understanding.

Thursday, January 26, 2017

C Library -

The assert.h header file of the C Standard Library provides a macro called assert which can be used to verify assumptions made by the program and print a diagnostic message if this assumption is false.

C Library -

The ctype.h header file of the C Standard Library declares several functions that are useful for testing and mapping characters.
All the functions accepts int as a parameter, whose value must be EOF or representable as an unsigned char.
All the functions return non-zero (true) if the argument c satisfies the condition described, and zero(false) if not.

C Library -

The errno.h header file of the C Standard Library defines the integer variable errno, which is set by system calls and some library functions in the event of an error to indicate what went wrong. This macro expands to a modifiable lvalue of type int, therefore it can be both read and modified by a program.

C Library -

The float.h header file of the C Standard Library contains a set of various platform-dependent constants related to floating point values. These constants are proposed by ANSI C. They allow making more portable programs. Before checking all the constants, it is good to understand that floating-point number is composed of following four elements −

C Library -

The limits.h header determines various properties of the various variable types. The macros defined in this header, limits the values of various variable types like char, int and long.
These limits specify that a variable cannot store any value beyond these limits, for example an unsigned character can store up to a maximum value of 255.

C Library -

The locale.h header defines the location specific settings, such as date formats and currency symbols. You will find several macros defined along with an important structure struct lconv and two important functions listed below.

C Library -

The math.h header defines various mathematical functions and one macro. All the functions available in this library take double as an argument and return double as the result.

C Library -

The setjmp.h header defines the macro setjmp(), one function longjmp(), and one variable type jmp_buf, for bypassing the normal function call and return discipline.

C Library -

The signal.h header defines a variable type sig_atomic_t, two function calls, and several macros to handle different signals reported during a program's execution.

C Library -

The stdarg.h header defines a variable type va_list and three macros which can be used to get the arguments in a function when the number of arguments are not known i.e. variable number of arguments.
A function of variable arguments is defined with the ellipsis (,...) at the end of the parameter list.

C Library -

The stddef.h header defines various variable types and macros. Many of these definitions also appear in other headers.

C Library -

The stdio.h header defines three variable types, several macros, and various functions for performing input and output.

C Library -

The stdlib.h header defines four variable types, several macros, and various functions for performing general functions.

C Library -

The string.h header defines one variable type, one macro, and various functions for manipulating arrays of characters.

C Library -

The time.h header defines four variable types, two macro and various functions for manipulating date and time.

Discuss C Standard Library

C is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis M. Ritchie at the Bell Telephone Laboratories to develop the Unix operating system.

C Tutorial

Audience

This tutorial is designed for software programmers with a need to understand the C programming language starting from scratch. This tutorial will give you enough understanding on C programming language from where you can take yourself to higher level of expertise.

C - Useful Resources

The following resources contain additional information on C. Please use them to get more in-depth knowledge on this topic.

AWK - Overview

AWK is an interpreted programming language. It is very powerful and specially designed for text processing. Its name is derived from the family names of its authors − Alfred Aho, Peter Weinberger, and Brian Kernighan.

AWK - Environment

This chapter describes how to set up the AWK environment on your GNU/Linux system.

Installation Using Package Manager

AWK - Workflow

To become an expert AWK programmer, you need to know its internals. AWK follows a simple workflow − Read, Execute, and Repeat. The following diagram depicts the workflow of AWK −

AWK - Basic Syntax

AWK is simple to use. We can provide AWK commands either directly from the command line or in the form of a text file containing AWK commands.

AWK - Basic Examples

This chapter describes several useful AWK commands and their appropriate examples. Consider a text file marks.txt to be processed with the following content −

1) Amit     Physics   80
2) Rahul    Maths     90
3) Shyam    Biology   87
4) Kedar    English   85
5) Hari     History   89

AWK - Built-in Variables

AWK provides several built-in variables. They play an important role while writing AWK scripts. This chapter demonstrates the usage of built-in variables.

Standard AWK variables

The standard AWK variables are discussed below.

AWK - Operators

Like other programming languages, AWK also provides a large set of operators. This chapter explains AWK operators with suitable examples.

AWK - Regular Expressions

AWK is very powerful and efficient in handling regular expressions. A number of complex tasks can be solved with simple regular expressions. Any command-line expert knows the power of regular expressions.
This chapter covers standard regular expressions with suitable examples.

AWK - Arrays

AWK has associative arrays and one of the best thing about it is – the indexes need not to be continuous set of number; you can use either string or number as an array index. Also, there is no need to declare the size of an array in advance – arrays can expand/shrink at runtime.
Its syntax is as follows −

AWK - Control Flow

Like other programming languages, AWK provides conditional statements to control the flow of a program. This chapter explains AWK's control statements with suitable examples.

AWK - Loops

This chapter explains AWK's loops with suitable example. Loops are used to execute a set of actions in a repeated manner. The loop execution continues as long as the loop condition is true.

AWK - Built-in Functions

AWK has a number of functions built into it that are always available to the programmer. This chapter describes Arithmetic, String, Time, Bit manipulation, and other miscellaneous functions with suitable examples.

AWK - User Defined Functions

Functions are basic building blocks of a program. AWK allows us to define our own functions. A large program can be divided into functions and each function can be written/tested independently. It provides re-usability of code.
Given below is the general format of a user-defined function −

AWK - Output Redirection

So far, we displayed data on standard output stream. We can also redirect data to a file. A redirection appears after the print or printf statement. Redirections in AWK are written just like redirection in shell commands, except that they are written inside the AWK program. This chapter explains redirection with suitable examples.

AWK - Pretty Printing

So far we have used AWK's print and printf functions to display data on standard output. But printf is much more powerful than what we have seen before. This function is borrowed from the C language and is very helpful while producing formatted output. Below is the syntax of the printf statement −

AWK - Overview

AWK - Useful Resources

The following resources contain additional information on AWK. Please use them to get more in-depth knowledge on this.

Discuss AWK

This tutorial takes you through AWK, one of the most prominent text-processing utility on GNU/Linux. It is very powerful and uses simple programming language. It can solve complex text processing tasks with a few lines of code.

What is Assembly Language?

Each personal computer has a microprocessor that manages the computer's arithmetical, logical, and control activities.
Each family of processors has its own set of instructions for handling various operations such as getting input from keyboard, displaying information on screen and performing various other jobs.

Try it Option Online
We already have set up NASM assembler to experiment with Assembly programming online, so that you can execute all the available examples online at the same time when you are doing your theory work.

Assembly - Basic Syntax

An assembly program can be divided into three sections −

The data section,
The bss section, and
The text section.

Assembly - Memory Segments

We have already discussed the three sections of an assembly program. These sections represent various memory segments as well.
Interestingly, if you replace the section keyword with segment, you will get the same result. Try the following code −

Assembly - Registers

Processor operations mostly involve processing data. This data can be stored in memory and accessed from thereon. However, reading data from and storing data into memory slows down the processor, as it involves complicated processes of sending the data request across the control bus and into the memory storage unit and getting the data through the same channel.

Assembly - System Calls

System calls are APIs for the interface between the user space and the kernel space. We have already used the system calls. sys_write and sys_exit, for writing into the screen and exiting from the program, respectively.

Assembly - Addressing Modes

Most assembly language instructions require operands to be processed. An operand address provides the location, where the data to be processed is stored. Some instructions do not require an operand, whereas some other instructions may require one, two, or three operands.

Assembly - Variables

NASM provides various define directives for reserving storage space for variables. The define assembler directive is used for allocation of storage space. It can be used to reserve as well as initialize one or more bytes.

Assembly - Constants

There are several directives provided by NASM that define constants. We have already used the EQU directive in previous chapters. We will particularly discuss three directives −

The INC Instruction

The INC instruction is used for incrementing an operand by one. It works on a single operand that can be either in a register or in memory.

Assembly - Logical Instructions

The processor instruction set provides the instructions AND, OR, XOR, TEST, and NOT Boolean logic, which tests, sets, and clears the bits according to the need of the program.
The format for these instructions −

Assembly - Conditions

Conditional execution in assembly language is accomplished by several looping and branching instructions. These instructions can change the flow of control in a program. Conditional execution is observed in two scenarios −

Assembly - Loops

The JMP instruction can be used for implementing loops. For example, the following code snippet can be used for executing the loop-body 10 times.

MOV CL, 10
L1:
<LOOP-BODY>

Assembly - Numbers

Numerical data is generally represented in binary system. Arithmetic instructions operate on binary data. When numbers are displayed on screen or entered from keyboard, they are in ASCII form.

Assembly - Strings

We have already used variable length strings in our previous examples. The variable length strings can have as many characters as required. Generally, we specify the length of the string by either of the two ways −

Explicitly storing string length
Using a sentinel character

Assembly - Arrays

We have already discussed that the data definition directives to the assembler are used for allocating storage for variables. The variable could also be initialized with some specific value. The initialized value could be specified in hexadecimal, decimal or binary form.

Assembly - Procedures

Procedures or subroutines are very important in assembly language, as the assembly language programs tend to be large in size. Procedures are identified by a name. Following this name, the body of the procedure is described which performs a well-defined job. End of the procedure is indicated by a return statement.

Assembly - Recursion

A recursive procedure is one that calls itself. There are two kind of recursion: direct and indirect. In direct recursion, the procedure calls itself and in indirect recursion, the first procedure calls a second procedure, which in turn calls the first procedure.

Assembly - Macros

Writing a macro is another way of ensuring modular programming in assembly language.

A macro is a sequence of instructions, assigned by a name and could be used anywhere in the program.
In NASM, macros are defined with %macro and %endmacro directives.
The macro begins with the %macro directive and ends with the %endmacro directive.

Assembly - File Management

The system considers any input or output data as stream of bytes. There are three standard file streams −

Standard input (stdin),
Standard output (stdout), and
Standard error (stderr).

Assembly - Memory Management

The sys_brk() system call is provided by the kernel, to allocate memory without the need of moving it later. This call allocates memory right behind the application image in the memory. This system function allows you to set the highest available address in the data section.

Assembly - Introduction

What is Assembly Language?

Each personal computer has a microprocessor that manages the computer's arithmetical, logical, and control activities.

Assembly - Useful Resources

The following resources contain additional information on Assembly Programming. Please use them to get more in-depth knowledge on this topic.

Discuss Assembly Programming

Assembly language is a low-level programming language for a computer or other programmable device specific to a particular computer architecture in contrast to most high-level programming languages, which are generally portable across multiple systems. Assembly language is converted into executable machine code by a utility program referred to as an assembler like NASM, MASM, etc.

Arduino - Overview

Arduino is a prototype platform (open-source) based on an easy-to-use hardware and software. It consists of a circuit board, which can be programed (referred to as a microcontroller) and a ready-made software called Arduino IDE (Integrated Development Environment), which is used to write and upload the computer code to the physical board.
The key features are −

Arduino - Board Description

In this chapter, we will learn about the different components on the Arduino board. We will study the Arduino UNO board because it is the most popular board in the Arduino board family. In addition, it is the best board to get started with electronics and coding. Some boards look a bit different from the one given below, but most Arduinos have majority of these components in common.

Arduino - Installation

After learning about the main parts of the Arduino UNO board, we are ready to learn how to set up the Arduino IDE. Once we learn this, we will be ready to upload our program on the Arduino board.
In this section, we will learn in easy steps, how to set up the Arduino IDE on our computer and prepare the board to receive the program via USB cable.

Arduino - Program Structure

In this chapter, we will study in depth, the Arduino program structure and we will learn more new terminologies used in the Arduino world. The Arduino software is open-source. The source code for the Java environment is released under the GPL and the C/C++ microcontroller libraries are under the LGPL.
Sketch − The first new terminology is the Arduino program called “sketch”.

Arduino - Data Types

Data types in C refers to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in the storage and how the bit pattern stored is interpreted.

Arduino - Variables & Constants

Before we start explaining the variable types, a very important subject we need to make sure, you fully understand is called the variable scope.

Arduino - Operators

An operator is a symbol that tells the compiler to perform specific mathematical or logical functions. C language is rich in built-in operators and provides the following types of operators −

Arduino - Control Statements

Decision making structures require that the programmer specify one or more conditions to be evaluated or tested by the program. It should be along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.

Arduino - Loops

Programming languages provide various control structures that allow for more complicated execution paths.
A loop statement allows us to execute a statement or group of statements multiple times and following is the general form of a loop statement in most of the programming languages −

Arduino - Functions

Functions allow structuring the programs in segments of code to perform individual tasks. The typical case for creating a function is when one needs to perform the same action multiple times in a program.
Standardizing code fragments into functions has several advantages −

Arduino - Strings

Strings are used to store text. They can be used to display text on an LCD or in the Arduino IDE Serial Monitor window. Strings are also useful for storing the user input. For example, the characters that a user types on a keypad connected to the Arduino.
There are two types of strings in Arduino programming −

Arduino - String Object

The second type of string used in Arduino programming is the String Object.

What is an Object?

An object is a construct that contains both data and functions. A String object can be created just like a variable and assigned a value or string. The String object contains functions (which are called

Arduino - Arrays

An array is a consecutive group of memory locations that are of the same type. To refer to a particular location or element in the array, we specify the name of the array and the position number of the particular element in the array.

Arduino - I/O Functions

The pins on the Arduino board can be configured as either inputs or outputs. We will explain the functioning of the pins in those modes. It is important to note that a majority of Arduino analog pins, may be configured, and used, in exactly the same manner as digital pins.

Arduino - Advanced I/O Function

In this chapter, we will learn some advanced Input and Output Functions.

analogReference() Function

Configures the reference voltage used for analog input (i.e. the value used as the top of the input range). The options are −

Arduino - Character Functions

All data is entered into computers as characters, which includes letters, digits and various special symbols. In this section, we discuss the capabilities of C++ for examining and manipulating individual characters.

Arduino - Math Library

The Arduino Math library (math.h) includes a number of useful mathematical functions for manipulating floating-point numbers.

Arduino - Trigonometric Functions

You need to use Trigonometry practically like calculating the distance for moving object or angular speed. Arduino provides traditional trigonometric functions (sin, cos, tan, asin, acos, atan) that can be summarized by writing their prototypes. Math.h contains the trigonometry function's prototype.

Arduino - Due & Zero

The Arduino Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU. It is the first Arduino board based on a 32-bit ARM core microcontroller.
Important features −

Arduino - Pulse Width Modulation

Pulse Width Modulation or PWM is a common technique used to vary the width of the pulses in a pulse-train. PWM has many applications such as controlling servos and speed controllers, limiting the effective power of motors and LEDs.

Arduino - Random Numbers

To generate random numbers, you can use Arduino random number functions. We have two functions −

randomSeed(seed)
random()

randomSeed (seed)

Arduino - Interrupts

Interrupts stop the current work of Arduino such that some other work can be done.
Suppose you are sitting at home, chatting with someone. Suddenly the telephone rings. You stop chatting, and pick up the telephone to speak to the caller.

Arduino - Communication

Hundreds of communication protocols have been defined to achieve this data exchange. Each protocol can be categorized into one of the two categories: parallel or serial.

Arduino - Inter Integrated Circuit

Inter-integrated circuit (I2C) is a system for serial data exchange between the microcontrollers and specialized integrated circuits of a new generation. It is used when the distance between them is short (receiver and transmitter are usually on the same printed board). Connection is established via two conductors. One is used for data transfer and the other is used for synchronization (clock signal).

Arduino - Serial Peripheral Interface

A Serial Peripheral Interface (SPI) bus is a system for serial communication, which uses up to four conductors, commonly three. One conductor is used for data receiving, one for data sending, one for synchronization and one alternatively for selecting a device to communicate with.

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