Compilare: user.cpp: In function ‘void in(int)’: user.cpp:11:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<v[el%p].size();j++) ^ user.cpp: In function ‘void eras(int)’: user.cpp:24:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] { for (int i=0;i<v[a%p].size();i++) ^ user.cpp: In function ‘bool f(int)’: user.cpp:36:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v[el%p].size();i++) ^ user.cpp:43:1: warning: control reaches end of non-void function [-Wreturn-type] } ^