Returns a string representing the indicated sub-match.

Ifn==0, a string representing entire matched expression is returned.

If0< n&& n< size(), a string representingn^th sub-match is returned.

ifn>= size(), a string representing the unmatched match is returned.

The call is equivalent tostring_type((*this)[n]);

ready() must betrue. Otherwise, the behavior is undefined.

[edit]Parameters

[edit]Return value

Returns a string representing the specified match or sub match.

[edit]Example

#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';}

entire match: aaabsubmatch #1: aentire match: aaabsubmatch #1: aa

[edit]See also

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