std::match_results<BidirIt,Alloc>::str (3) - Linux Manuals

std::match_results<BidirIt,Alloc>::str: std::match_results<BidirIt,Alloc>::str

NAME

std::match_results<BidirIt,Alloc>::str - std::match_results<BidirIt,Alloc>::str

Synopsis

string_type str( size_type n = 0 ) const; (since C++11)

Returns a string representing the indicated sub-match.
If n == 0, a string representing entire matched expression is returned.
If n > 0 && n < size(), a string representing nth sub-match is returned.
if n >= size(), a string representing the unmatched match is returned.
The call is equivalent to string_type((*this)[n]);

Parameters

n - integral number specifying which match to return

Return value

Returns a string representing the specified match or sub match.

Example

// Run this code

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

  int main()
  {
      std::string target("baaaby");
      std::smatch sm;

      std::regex re1("a(a)*b");
      std::regex_search(target, sm, re1);
      std::cout << "entire match: " << sm.str(0) << '\n'
                << "submatch #1: " << sm.str(1) << '\n';

      std::regex re2("a(a*)b");
      std::regex_search(target, sm, re2);
      std::cout << "entire match: " << sm.str(0) << '\n'
                << "submatch #1: " << sm.str(1) << '\n';

  }

Output:

  entire match: aaab
  submatch #1: a
  entire match: aaab
  submatch #1: aa