Dasar c++ : Program c++ bilangan faktorial

Berikut ini listing program c++ mencetak bilangan fakorial
 #include <iostream.h>
main(){
int a,b,c;
c=1;
cout<<"masukkan bilangan : ";
cin>>a;
for (b=a; b>0; b--)
c=c*b;
cout<<a<<" ! ="<<c<<endl;}