Compilare: user.cpp: In function ‘int main()’: user.cpp:55:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<X.size()-1;++j) ^ user.cpp:58:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=X.size()-1;j<Y.size();++j) ^ user.cpp:64:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<Y.size()-1;++j) ^ user.cpp:69:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=Y.size()+1;j<X.size();++j) ^