NAME

std::match_results::position - std::match_results::position

Synopsis

difference_type position( size_type n = 0 ) const; (since C++11)

Returns the position of the first character of the specified sub-match.

If n == 0, the position of the first character of the entire matched expression is
returned.

If n > 0 && n < size(), the position of the first character of the nth sub-match is
returned.

if n >= size(), a position of the first character of the unmatched match is
returned.

Parameters

n - integral number specifying which match to examine

Return value

The position of the first character of the specified match or sub-match.

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::regex_match(target, sm, re);
std::cout << sm.position(1) << '\n';
}

Output:

1

See also

operator[] returns specified sub-match
(public member function)