This tutorial is to find the sum of digits of a number using for loop and while loop in C. You need to have knowledge of the following topics in C.
Explanation:
To find the sum of the digits means to add all the digits present in the number. For example: consider a number 123, sum of the digits of 123 will be 1+2+3 = 6.
C Program to find the sum of the digits of a number using for loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | #include <stdio.h> int main() { int num, sum = 0, rem, i; printf("Enter a number: "); scanf("%d", &num); for (i = num; num != 0; num = num / 10) { rem = num % 10; sum = sum + rem; } printf("Sum of digits of a number: %d", sum); return 0; } |
Output:
Enter a number: 245
Sum of digits of a number: 11
C Program to find the sum of the digits of a number using while loop
To find the sum of a digit in c using while loop is similar to the for loop, here you need to initialize i with num after the input is taken from the user and i increment is done inside the while body as shown below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | #include <stdio.h> int main() { int num, sum = 0, rem, i; printf("Enter a number: "); scanf("%d", &num); i = num; while (num != 0) { rem = num % 10; sum = sum + rem; num = num / 10; } printf("Sum of digits of a number: %d", sum); return 0; } |
Output:
Enter a number: 123
Sum of digits of a number: 6
C Program to find the sum of the digits of a number using recursion function
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #include <stdio.h> int sumDigits(int); int main() { int num, result; printf("Enter a number: "); scanf("%d", &num); result = sumDigits(num); printf("Sum of digits of a number: %d", result); return 0; } int sumDigits(int n) { if (n == 0) return 0; return (n % 10 + sumDigits(n / 10)); //recursion call } |
Output:
Enter a number: 123
Sum of digits of a number: 6
Learn more on recursion.