Write a C program to enter any number and calculate sum of digits using for loop. C program to find sum of digits of a number. How to find sum of digits of a number in C programming. Logic to find sum of digits of a given number in C program.

**Example**

**Input**

Input any number: 1234

**Output**

Sum of digits: 10

## Required knowledge

Basic C programming, While loop

## Logic to find sum of digits

The main idea to find sum of digits can be divided in three steps -

- Extract last digit of the number.
- Add the extracted last digit to sum.
- Remove the last digit. As it is processed and not required any more.

If you repeat above three steps till the number becomes `0`

. Finally you will be left with sum of digits.

Below is the step by step descriptive logic to find sum of digits.

- Input number from user. Store it in some variable say num.
- Find last digit of the number by performing modular division i.e. lastDigit = num % 10.
- Add last digit just found above to sum i.e. sum = sum + lastDigit.
- Remove last digit from number by dividing the number by
`10`

i.e. num = num / 10 - Repeat step 2-4 till number becomes
`0`

. Finally you will be left with the sum of digits in sum.

## Program to find sum of digits

```
/**
* C program to find sum of its digits of a number
*/
#include <stdio.h>
int main()
{
int num, sum=0;
/* Input a number from user */
printf("Enter any number to find sum of its digit: ");
scanf("%d", &num);
/* Repeat till num becomes 0 */
while(num!=0)
{
/* Find the last digit of num and add to sum */
sum += num % 10;
/* Removes last digit from num */
num = num / 10;
}
printf("Sum of digits = %d", sum);
return 0;
}
```

Output

Enter any number to find sum of its digit: 1234 Sum of digits = 10

Happy coding 😉

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