C program to calculate sum of all digits using recursion

#include <stdio.h>

//function to calculate sum of all digits

int sumDigits(int num)

{

    static int sum=0;

    if(num>0)

    {

        sum+=(num%10); //add digit into sum

        sumDigits(num/10);

    }

    else

    {

        return sum;

    }

}

int main()

{

    int number,sum;    

    printf("Enter a positive integer number: ");

    scanf("%d",&number);    

    sum=sumDigits(number);    

    printf("Sum of all digits are: %d\n",sum);

     return 0;

}