Compilare: user.cpp: In function ‘int main()’: user.cpp:37:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();i++) ^ user.cpp:51:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();i++) ^ user.cpp:60:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[key].size()&&ok==0;j++) ^