program C++ menentukan nilai mahasiswa

#include <iostream.h>
void main()
{
int nilai;
cout<<"nilai mahasiswa"<<endl<<endl;
cout<<"masukkan nilai anda:";
cin>>nilai;
cout<<endl;
if((100.00>=nilai)&&(nilai>=8.00))
cout<<"A";
else
if((7.99>=nilai)&&(nilai>=7.00))
cout<<"B";
if((6.99>=nilai)&&(nilai>=6.00))
cout<<"C";
if((5.99>=nilai)&&(nilai>=5.00))
cout<<"D";
if((4.99>=nilai)&&(nilai>=4.00))
cout<<"E";
if((3.99>=nilai)&&(nilai>=0.00))
cout<<"E";
}