Sum of Digits of a Given Number in C

Flow Control
If-else Statement in C
Programs on if-else
Switch Case in C
Switch case Programs
Conditional Operator
While loop in C
Do-while loop in C
While vs do-while
For loop in C
Break keyword in C
Continue keyword in C
Break vs Exit in C
Goto keyword in C
☕️ Flow Control Programs
Largest in 3 Numbers
Find Grade of student
Find the absolute value
Vowel or Consonant
Leap Year Program
Simple calculator in C
Check Odd or Even 
Roots of Quadratic Equation
Find Reverse of Number
Factors of a number in C
Generate Multiplication table
Find Power of a Number
Find GCD and LCM
Find factorial of Number
Count Number of Digits
Sum of digits in Number
Sum of N Natural Numbers
Sum of Squares of Natural No.
Find Sum of Odd Numbers
Find the Sum of Series
Find Fibonacci series in C
Sum of the Fibonacci series
Sum until enters +ve numbers
Sum of max 10 no. & Skip -ve
☕️ C Conversion Programs
Celsius to Fahrenheit
Fahrenheit to Celsius
Decimal ↔ Binary
Decimal ↔ Octal
Octal ↔ Binary in C
☕️ Number Programs in C
Prime Number in C
Strong Number in C
Krishnamurthy Number
Neon Number in C
Palindrome number
Perfect Number in C
Armstrong Number
☕️ Pattern Programs in C
Pattern programs in C
Printing pattern using loops
Floyd’s triangle Program
Pascal Triangle Program
Pyramid Star Pattern in C
Diamond Pattern Programs
Half Diamond pattern in C
Print Diamond Pattern
Hollow Diamond Pattern
Diamond Pattern of Numbers

The sum of digits in C can be written using loops. To find the sum of the digits of a given number we need to follow below procedures,

1) Take a number as input
2) Declare two variables lastDigit and sum and initialize the sum variable with 0
3) Find the last digit of the number, lastDigit = number%10
4) Add the value of lastDigit to the variable sum
5) Remove the last digit of the number. number = number/10
6) Repeat 3 to 5 steps until the number does not becomes 0.

Prerequisites:- While loop in C, For loop in C

The sum of digits of the number 54321 = 5+4+3+2+1 = 15

Sum of Digits in C using the while loop

 #include<stdio.h>
 int main()
 {
     int number,lastDigit,sum=0;

     printf("Enter any number: ");
     scanf("%d",&number);

     while(number!=0)
     {
         lastDigit=number%10;
         sum += lastDigit;
         number/=10;
     }

     printf("Sum of digits =  %d\n",sum);

     return 0;
 }

Output:-

Enter any number: 123456
Sum of digits = 21

The statements of the while loop also can be written in two-line as given below. In this case, the variable lastDigit is not required.

 while(number!=0)
 {
     sum += (number%10);
     number/=10;
 }

Using for loop

 #include<stdio.h>
 int main()
 {
     int number,sum;

     printf("Enter any number: ");
     scanf("%d",&number);

     for(sum = 0; number!=0; number/=10)
     {
         sum += (number%10);
     }

     printf("Sum of digits =  %d\n",sum);

     return 0;
 }

Output:-

Enter any number: 125
Sum of digits = 8

From for loop in the C language topic, we know that we can write more than one update expression inside the for loop. So, in above program we can reduce the number of lines of for loop. Don’t forget the semicolon at the end of the for loop.

for(sum = 0; number!=0; sum += (number%10), number/=10);

Sum of Digits in C without using a loop

In this case. we can use a recursive function to find the sum of digits of a given number.

 #include<stdio.h>
 int sumOfDigits(int n)
 {
   if(n==0) return 0;
   else return (n%10)+sumOfDigits(n/10);
 }
 int main()
 {
     int number, sum;

     printf("Enter any number: ");
     scanf("%d",&number);

     sum = sumOfDigits(number);

     printf("Sum of digits =  %d\n",sum);

     return 0;
 }

In this program, we developed a recursive function sumOfDigits(), this function finds the sum of the digits of a given number by the recursive way. A function that calls itself is called the recursive function. Recursion is one the way to find the solution to the program.

If you enjoyed this post, share it with your friends. Do you want to share more information about the topic discussed above or you find anything incorrect? Let us know in the comments. Thank you!

Flow Control
If-else Statement in C
Programs on if-else
Switch Case in C
Switch case Programs
Conditional Operator
While loop in C
Do-while loop in C
While vs do-while
For loop in C
Break keyword in C
Continue keyword in C
Break vs Exit in C
Goto keyword in C
☕️ Flow Control Programs
Largest among 3 Numbers
Find Grade of student
Find the absolute value
Check Vowel or Consonant
Leap Year Program
Simple calculator in C
Check Odd or Even 
Roots of Quadratic Equation
Find Reverse of Number
Factors of a number in C
Generate Multiplication table
Find Power of a Number
Find GCD and LCM
Find factorial of Number
Count Number of Digits
Sum of digits in Number
Sum of N Natural Numbers
Sum of Squares of Natural No.
Find Sum of Odd Numbers
Find the Sum of Series
Find Fibonacci series in C
Sum of the Fibonacci series
Sum until enters +ve numbers
Sum of max 10 no. & Skip -ve
☕️ C Conversion Programs
Celsius to Fahrenheit
Fahrenheit to Celsius
Decimal ↔ Binary
Decimal ↔ Octal
Octal ↔ Binary in C
☕️ Number Programs in C
Prime Number in C
Strong Number in C
Krishnamurthy Number
Neon Number in C
Palindrome number
Perfect Number in C
Armstrong Number
☕️ Pattern Programs in C
Pattern programs in C
Printing pattern using loops
Floyd’s triangle Program
Pascal Triangle Program
Pyramid Star Pattern in C
Diamond Pattern Programs
Half Diamond pattern in C
Print Diamond Pattern
Hollow Diamond Pattern
Diamond Pattern of Numbers

Leave a Comment

Your email address will not be published. Required fields are marked *