NAME

std::match_results::size - std::match_results::size

Synopsis

size_type size() const noexcept; (since C++11)

Returns the number of submatches, i.e. std::distance(begin(), end()).

Returns 0 if *this does not represent the result of a successful match.

Parameters

(none)

Return value

The number of submatches

Complexity

Constant

Example

// Run this code

#include <iostream>
#include <regex>
#include <string>

int main()
{
std::regex re("a(a)*b");
std::string target("aaab");
std::smatch sm;

std::cout << sm.size() << '\n';

std::regex_match(target, sm, re);
std::cout << sm.size() << '\n';
}

Output:

0
2

See also

begin returns iterator to the beginning of the list of sub-matches
cbegin (public member function)
end returns iterator to the end of the list of sub-matches
cend (public member function)