Program Menentukan Nilai

/Program Menentukan Jenis Bilangan
# include <iostream.h>
# include <conio.h>
# include <string>

void main()
{
int na;
string nama;

cout<<"Masukkan Nama :";cin>>nama;
cout<<"Masukkan Nilai Angka :":cin>>na;

if (na>=80)
{
cout<<"Hallo"<<nama<<",Nilai Anda A";
}
else if (na>=60)
{
cout<<"Hallo"<<nama<<",Nilai Anda B";
}
else if (na>=40)
{
cout<<"Hallo"<<nama<<",Nilai Anda C";
}
else if (na>=20)
{
cout<<"Hallo"<<nama<<",Nilai Anda D";
}
else if (na>=0)
{
cout<<"Hallo"<<nama<<",Nilai Anda E";
}
getch();
}