Compilare: main.cpp: In function 'std::vector<int> operator-(std::vector<int>, std::vector<int>)': main.cpp:84:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<x.size();i++){ ~^~~~~~~~~ main.cpp:85:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<y.size()) ~^~~~~~~~~