Compilare: user.cpp: In function ‘int main()’: user.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<v.size()){ ^ user.cpp:38:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(v[i].first==v[i-1].first && i<v.size()){ ^ user.cpp:46:98: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(v[i].second.first==v[i-1].second.first && v[i].first==v[i-1].first && i<v.size()){ ^