c++ - How to use <regex> in C++11 -

i'm trying use regular expression accept strings have sequences like

ifelseifelseififif 

so every else needs if, not every if needs else. know pen , paper simple regular expression ((if)*+(ifelse)*)* .now i'm not sure if i'll able library i've never used before. possible accept or reject string based on regular expression 1 wrote above?

i wrote sample feet wet , don't understand why returns false. isn't regex_search() supposed find substring matches? snippet prints nope every time.

#include <regex> #include <iostream> using namespace std;  int main(){   string sequence="ifelse";   regex rx("if");   if(regex_search(sequence.begin(),sequence.end(),rx)){     cout<<"match found"<<endl;   }else{     cout<<"nope"<<endl;   } } 

i'm using g++ 4.7 , have tried compiling both g++ -std=gnu+11 reg.cpp , g++ -std=c++11 reg.cpp

if compiling g++ may because regex not supported yet. see here current c++11 status in g++.