Compilare: main.cpp: In function 'int main()': main.cpp:103:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s1.size()<s2.size()) for (int i=0; i<s1.size(); ++i) cout<<s1[i].d<<" "<<s1[i].v1<<" "<<s1[i].v2<<"\n"; ~^~~~~~~~~~ main.cpp:104:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else for (int i=0; i<s2.size(); ++i) cout<<s2[i].d<<" "<<s2[i].v1<<" "<<s2[i].v2<<"\n"; ~^~~~~~~~~~