Compilare: user.cpp: In function ‘int main()’: user.cpp:20:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1; i<A.size(); i++) ^ user.cpp:30:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1; i<B.size(); i++) ^ user.cpp:37:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(w==A.size()) ^