SQL Kiwi (9/21/2012)
This is about twice as fast for me:...
public static int SumDigits(int Input)
{
int sum = 0;
for (int n = System.Math.Abs(Input); n > 0; sum += n % 10, n /= 10) ;
return sum;
}
...
Another way in c# :
public static int SumDigits(int Input) { return Input.ToString().Sum(c => c - '0'); }