C program to calculate the number of permutations of given digits code example

Example 1: Sum of digits of a number using recursion function c

/*  
 * C Program to find Sum of Digits of a Number using Recursion
 */
#include <stdio.h>
 
int sum (int a);
 
int main()
{
    int num, result;
 
    printf("Enter the number: ");
    scanf("%d", &num);
    result = sum(num);
    printf("Sum of digits in %d is %d\n", num, result);
    return 0;
}
 
int sum (int num)
{
    if (num != 0)
    {
        return (num % 10 + sum (num / 10));
    }
    else
    {
       return 0;
    }
}

Example 2: how to count digits and sum of digits in C

Enter the number
300
Given number = 300
Sum of the digits 300 = 3
 
 
Enter the number
16789
Given number = 16789
Sum of the digits 16789 = 31