Compilare: user.cpp: In function ‘int main()’: user.cpp:116:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b1.size();++i) ^ user.cpp:118:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b2.size();++i) ^ user.cpp:124:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b1.size();++i) ^ user.cpp:126:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b2.size();++i) ^ user.cpp:130:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b1.size();++i)cout<<b1[i].x<<" "<<b1[i].y<<endl; ^