Compilare: user.cpp: In function ‘int main()’: user.cpp:39:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s2.size()) ^ user.cpp:45:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==s1.size()) ^ user.cpp:63:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v1.size();i++) ^