Compilare: user.cpp: In function ‘int main()’: user.cpp:55:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(f>>x) {nr++; v[i].push_back(x); if(nr==i) {nr=0; i++;}} ^ user.cpp:65:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[n].size();i++) ^ user.cpp:68:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[k].size();i++) ^ user.cpp:73:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[n].size();i++) ^ user.cpp:78:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[k].size();i++) ^