Compilare: user.cpp: In function ‘int main()’: user.cpp:34:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<p1.size(); i++)out<<p1[i]<<" "; ^ user.cpp:36:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<p2.size(); i++)out<<p2[i]<<" "; ^