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Thread: Write a Java program and compute the sum of the digits of an integer.

  1. #1
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    Default Write a Java program and compute the sum of the digits of an integer.

    I need help with a program where I have to find the sum of the digits of an integer.

    For example, for the integer 32, the sum of the digits of the integer is: 3+2 = 5
    Or, for the integer 321, the sum of the digits of the integer is: 3+2+1 = 6

    One person gave me this code (but did not explain):
    class Digits
    {
    	public static void main(String args[])
    	{
    		int num = 25;
    		int sum = 0; 
     
    		while (num > 0) 
    		{
    			sum = (sum + num) % 10;
    			num = num / 10; 
    		}
    		System.out.println("The sum of the digits of 25 is: " + sum);
    	}
    }

    However, I'm having trouble understanding what's going on in the while statement. BTW, i've even tried it with the numbers above (32 and 321), but I still don't understand the input?

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    Super Moderator Norm's Avatar
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    Default Re: Write a Java program and compute the sum of the digits of an integer.

    what's going on in the while statement.
    It uses the value in num to control looping. As long as num > 0, it continues to loop.
    To see how the value of num changes add a print statement to print the value of num at the end of the loop just before the ending }
    If you don't understand my answer, don't ignore it, ask a question.

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