Compilare: main.cpp: In function 'int main()': main.cpp:57:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<m.size()-1;i++) ~^~~~~~~~~~~ main.cpp:60:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=i+1; j<m.size();j++) ~^~~~~~~~~ main.cpp:59:20: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized] x=(m[i].first*m[j].second); ^