#include <stdio.h>
void main()
{
int n, r, npr_var;
printf("Enter the value of n:");
scanf("%d", &n);
printf("\nEnter the value of r:");
scanf("%d", &r);
/* nPr is also known as P(n,r), the formula is:
* P(n,r) = n! / (n - r)! For 0 <= r <= n.
*/
npr_var = fact(n) / fact(n - r);
printf("\nThe value of P(%d,%d) is: %d",n,r,npr_var);
}
// Function for calculating factorial
int fact(int num)
{
int k = 1, i;
// factorial of 0 is 1
if (num == 0)
{
return(k);
}
else
{
for (i = 1; i <= num; i++)
{
k = k * i;
}
}
return(k);
}