Compilare: user.cpp: In function ‘void biti(std::string)’: user.cpp:18:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<x.size();i++){ ^ user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=x.size()-n;i++){ ^ user.cpp:28:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++){ ^ user.cpp:29:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i+1;j<v.size();j++){ ^ user.cpp: At global scope: user.cpp:42:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^