18.18. Write a function that gets two positive integers and returns nPr (Permutation).

#include<stdio.h>

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

{
long p;

int i;

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

return p;

}
void main()

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

getch ();
}