Compilare: user.cpp: In function ‘int main()’: user.cpp:38:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(val[x] == 0 || val[x] > v[x].size() - gr[x]) { ^ user.cpp:52:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(m[z] && val[z] > v[z].size() - gr[z]) ^