Chapter 4, Problem 11E

Write a program that calculates the sum of the digits of an integer. For example, the sum of the digits of the number 2155 is 2 + 1 + 5 + 5 or 13. The program should accept any arbitrary integer typed in by the user.

Explanation of Solution

Program:

The following program is used to sum the input digits using “do-while” condition:

//include the header file

#include <stdio.h>

//definition of main method

int main (void)

{

//declare the variables

int number, right_digit, s = 0;

//get the input from the user

printf("Enter your number.\n");

scanf("%i", &number);

//check the condition

do

{

//calculate the "right_digit"

right_digit = number % 10;

//calculate the "number"

number = number / 10;

//calculate the sum

s += right_digit;

}

while (number > 0);

//display newline

printf("The sum of the digit is: %i\n", s);

//return statement

return 0;

}

Explanation:

In the above program, declare the required header file. Inside the main method, declare the necessary variables. Get the number from the user and the “do-while” condition is used to add the input digits and finally display the result on the output screen.

Sample Output

Enter your number.

 2155

The sum of the digit is: 13