C++ Library -

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 −

• Target sequence (subject) − It is used to searched for the sequence pattern.
• Regular expression (pattern) − It is used to searched for in the target sequence.
• Matches array − Matches information is stored in one of the special match_results array types (such as cmatch or smatch).
• Replacement strin − This operation replaces the matches.

Regex operations

S.N.	Regex operation & description
1	regex_match It is a match sequence.
2	regex_search It is a search sequence.
3	regex_replace It is a replace matched sequence.

Iterator types

S.N.	Iterator type & description
1	regex_iterator It is a regex iterator.
2	regex_token_iterator It is a regex token iterator.

basic_regex instantiations

S.N.	Instantiation & description
1	regex It is a regex class.
2	wregex It is a wregex class.

match_results instantiations

S.N.	match_results instantiation & description
1	cmatch These are match_results for string literals.
2	wcmatch These are match_results for wide string literals.
3	smatch These are match_results for string objects.
4	wsmatch These are match_results for wide string objects.

sub_match instantiations

S.N.	sub_match instantiation & description
1	csub_match It is a sub_match for string literals.
2	wcsub_match It is a sub_match for wide string literals.
3	ssub_match It is a sub_match for strings.
4	wssub_match It is a sub_match for wide strings.

Namespaces

S.N.	Namespace & description
1	regex_constants It is a regex constants.