18.19. Write a function that gets two positive integers and returns nCr (Combination).

#include<stdio.h>

#include<conio.h>
long nCr(int n, int r)

{
long p;

int i;

if(n-r<r)

r=n-r;

p=1;

for(i=1;i<=r;p=p*(n-i+1)/i,i++);

return p;

}
void main()

{
int n, r;
clrscr ();
printf ("Enter first number: ");
scanf("%d",&n):
printf ("Enter second number: ");
scanf ("&d", &r):
printf ("nCr= %ld", nCr(n,r)); 

getch ();
}