Menghitung Kombinasi(nCr) dan Permutasi(nPr) C++

#include <iostream.h>
#include <stdio.h>
#include <conio.h>
void main()
{
int n,r;
long int fak(long int x);
long int kombinasi (long int n, int r);
long int permutasi (long int n, int r);
char ulang;
do
{
clrscr();
cout<<endl;
cout<<” Program Menghitung Kombinasi(nCr) dan Permutasi(nPr)”<<endl;
cout<<” ====================================================”<<endl;
cout<<” Masukkan Nilai n : “; cin>>n;
cout<<” Masukkan Nilai r : “; cin>>r;
cout<<endl;
kombinasi(n,r);
permutasi(n,r);
cout<<endl ;
cout<<” Program diullangi lagi (y/n)??”;cin>>ulang;
}while(ulang == ‘y’);
}
getch();
long int fak (long int n)
{
int f;
if (n<=1)
{    f=1;    }
else
{    f=n*fak(n-1);    }
return (f);
}
long int kombinasi (long int n, int r)
{
int Prts;
if (n>r){
Prts = fak(n)/(fak(n-r)*fak (r));
printf(” Kombinasinya(nCr) adalah: %d”,Prts);}
else if (n<r){
cout<<”data tak valid”;}
cout<<endl;
return(Prts);
}
long int permutasi (long int n, int r)
{
int Prts;
if (n>r){
Prts = fak (n)/fak(n-r);
printf(” Permutasinya(nPr) adalah: %d”,Prts);}
else if (n<r){
cout<<”data tak valid”;}
cout<<endl;
return(Prts);
}