In the following program we are calculating the value of nPr based on the given values of n and r. nPr can also be represented as P(n,r). **The formula of P(n, r) is**: n! / (n – r)!. For example P(6, 2) = 6! / (6-2)! => 720 / 24 = 30. We have implemented the same logic in the below C program.

#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); }

**Output:**

Enter the value of n: 5 Enter the value of r: 2 The value of P(6,2) is: 30

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