Compilare: main.cpp: In function 'int main()': main.cpp:48:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:53:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:88:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:93:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~