Program Menentukan Grade c++

#include <iostream.h>
#include <conio.h>
#include <ctype.h>

main()
{
char g;
   cout<<"Masukkan Grade Anda (A..E): ";cin>>g;
   g = toupper(g);
   if(g=='A'||g=='B'||g=='C')
   {
    cout<<"Anda lulus";
   }
   else if(g=='D'||g=='E')
   {
    cout<<"Anda Tidak Lulus";
   }
   else
    cout<<"Tidak Terdaftar!";
getch();
}