C Program to check if a number is divisible by sum of its digits

Given a number n we have to check whether the sum of its digits divide the number n or not. To find out we have to sum all the numbers starting from the unit place and then divide the number with the final sum.

Like we have a number “521” so we have to find the sum of its digit that will be “5 + 2 + 1 = 8” but 521 is not divisible by 8 without leaving any remainder.

Let’s take another example “60” where “6+0 = 6” which can divide 60 and will not leave any remainder.

Example

Input: 55
Output: No
Explanation: 5+5 = 10; 55 not divisible by 10
Input: 12
Output: Yes
Explanation: 1+2 = 3; 12 is divisible by 3

The approach used below is as follows −

To solve this problem we have to fetch each digit from the input and find the sum of each digit of a number, then check whether it is dividing the number or not.

• Take input
• Take each number from the unit place using and add it to a sum variable which should be initially zero
• Divide the input with the sum of the number.
• Return the result.

Algorithm

In function int isDivisible(long int num)
   Step 1-> Declare and initialize temp = num, sum = 0
   Step 2-> Loop While num
      Declare and initialize k as num % 10
   Set sum as sum + k
      Set num as num / 10
   End Loop
   Step 3-> If temp % sum == 0 then,
      Return 1
   Step 4-> Return 0
      End function
In main()
   Step 1-> Declare and initialize num as 55
   Step 2-> If isDivisible(num) then,
      Print "yes "
   Step 3-> Else
Print "no "

Example

 Live Demo

#include <stdio.h>
// This function will check
// whether the given number is divisible
// by sum of its digits
int isDivisible(long int num) {
   long int temp = num;
   // Find sum of digits
   int sum = 0;
   while (num) {
      int k = num % 10;
      sum = sum + k;
      num = num / 10;
   }
   // check if sum of digits divides num
   if (temp % sum == 0)
      return 1;
      return 0;
}
int main() {
   long int num = 55;
   if(isDivisible(num))
      printf("yes
");
   else
      printf("no
");
      return 0;
}

Output

If run the above code it will generate the following output −

No