Compilare: user.cpp: In function ‘int main()’: user.cpp:26:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V[1].size();i++) ^ user.cpp:33:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=V[1].size();i<V[3].size();i++) ^ user.cpp:42:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V[3].size();i++) ^ user.cpp:49:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=V[3].size();i<V[1].size();i++) ^