The Search Result match_results

The object of type std::match_results is the result of a std::regex_match or std::regex_search. std::match_results is a sequential container having at least one capture group of a std::sub_match object. The std::sub_match objects are sequences of characters.

What is a capture group?

Capture groups allow it to further analyse the search result in a regular expression. They are defined by a pair of parentheses ( ). The regular expression ((a+)(b+)(c+)) has four capture groups: ((a+)(b+)(c+)), (a+), (b+) and (c+) The total result is the 0th capture group.

C++ has four types of synonyms of type std::match_results:

typedef match_results<const char*> cmatch;
typedef match_results<const wchar_t*> wcmatch;
typedef match_results<string::const_iterator> smatch;
typedef match_results<wstring::const_iterator> wsmatch;

The search result std::smatch smatch has a powerful interface.

...

Interface of std::smatch