C program to calculate the value of nPr

nPr represents n permutation r and value of nPr is (n!) / (n-r)!.

C

#include<stdio.h>

int fact(int n)
{
    if (n <= 1)
        return 1;
    return n*fact(n-1);
}

int nPr(int n, int r)
{
    return fact(n)/fact(n-r);
}

int main()
{
    int n, r;
    printf("Enter n: ");
    scanf("%d", &n);

    printf("Enter r: ");
    scanf("%d", &r);

    printf("%dP%d is %d", n, r, nPr(n, r));

    return 0;
}

Enter n: 5
Enter r: 2
5P2 is 20 

Time Complexity: O(n)

Auxiliary Space: O(n)

Please refer Permutation Coefficient for efficient methods to compute nPr.