Sum of digits in C#

Question

What\'s the fastest and easiest to read implementation of calculating the sum of digits?

I.e. Given the number: 17463 = 1 + 7 + 4 + 6 + 3 = 21

Answer 1

private static int getDigitSum(int ds)
{
    int dssum = 0;            
    while (ds > 0)
    {
        dssum += ds % 10;
        ds /= 10;
        if (dssum > 9)
        {                
            dssum -= 9;
        }
    }
    return dssum;
}

This is to provide the sum of digits between 0-9

Answer 2

int j, k = 1234;
for(j=0;j+=k%10,k/=10;);

Answer 3

The simplest and easiest way would be using loops to find sum of digits.

int sum = 0;
int n = 1234;

while(n > 0)
{
    sum += n%10;
    n /= 10;
}

Answer 4

I like the chaowman's response, but would do one change

int result = 17463.ToString().Sum(c => Convert.ToInt32(c));

I'm not even sure the c - '0', syntax would work? (substracting two characters should give a character as a result I think?)

I think it's the most readable version (using of the word sum in combination with the lambda expression showing that you'll do it for every char). But indeed, I don't think it will be the fastest.

Answer 5

You could do it arithmetically, without using a string:

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

Answer 6

I use

int result = 17463.ToString().Sum(c => c - '0');

It uses only 1 line of code.