Recursive function that count with local var

Question

I'm having a question about recursive functions.

I've made this little example program that counts the individual numbers in an integers: example: 123 = 6 because 1 + 2 + 3 = 6.

Now I've made it with a static int and this recursive functions:

  static int totalNumbers(int a)
  { 
    if(a <= 0)
      return sum;
    else
    {
      sum += a % 10;
      return totalNumbers(a/10);
    }
  }

The function works like a charm but my question is, can I make it without a static int called sum? Is there a way that I can define a integer sum in the function and let them count up with a local var or is it not possible?

Kind regards,

Answer 1

Of course:

static int totalNumbers(int a)
  { 
    if(a <= 0)
      return 0;
    else
    {
      return (a % 10) + totalNumbers(a/10);
    }
  }

Answer 2

static int totalNumbers(int a)
{
    return a < 10 ? a : (a % 10) + totalNumbers(a / 10);
}