Sum of Digits Program in C of a given Number

In mathematics, the sum of digits a natural number in a given number base is the sum of all its digits.

For example, the sum of digits for the decimal number 9045 would be

9+0+4+5=18

Algorithm for sum of digits in a given number:

Get the number
Declare a variable to store the sum and set it to 0
Repeat the next two steps till the number is not 0
Get the rightmost digit of the number with help of the remainder ‘%’ operator by dividing it by 10 and add it to sum.
Divide the number by 10 with help of ‘/’ operator to remove the rightmost digit.
Print or return the sum

Now we will see how to find the sum of digits in C

Sum of Digits Program in C (Iterative)

// C program to compute sum of digits in

#include <stdio.h>
 
int getSum(int n)
{
    int sum = 0;
    while (n != 0) {
        sum = sum + n % 10;
        n = n / 10;
    }
    return sum;
}
 
int main()
{
    int n = 9045;
    printf(" %d ", getSum(n));
    return 0;
}

The Output will be

Number entered: 9045
Sum = 18

Also see the C Program to Check Armstrong Number