Compilare: main.cpp: In function 'int main()': main.cpp:15:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<=s.size(); i++) ~^~~~~~~~~~ main.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(phi[i]==a.size()) ~~~~~~^~~~~~~~~~