How to write a recursive method to return the sum of digits in an int?

Question

So this is my code so far.

    public int getsum (int n){
        int num = 23456;
        int total = 0;
        while (num != 0) {
            total += num         


        

Answer 1

This works for positive numbers.

public int sumDigits(int n) {
  int sum = 0;
  if(n == 0){
  return 0;
  }
  sum += n % 10; //add the sum
  n /= 10; //keep cutting
  return sum + sumDigits(n); //append sum to recursive call
}

Answer 2

Short, recursive and does the job:

int getsum(int n) {
   return n == 0 ? 0 : n % 10 + getsum(n/10);
}

Answer 3

public static int sumOfDigit(int num){
    int sum=0;
    if (num == 0)
    return sum;
            sum = num%10 + sumOfDigit(num/10);
    return sum;
}
public static void main(String args[]) {
    Scanner input=new Scanner(System.in);
    System.out.print("Input num : ");
    int num=input.nextInt();
    int s=sumOfDigit(num);
    System.out.println("Sum = "+s);
}

}

Answer 4

public int sumDigits(int n) {
    return (n - 1) % 9 + 1;
}

Answer 5

    import java.util.Scanner;
public class Adder {
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a number: ");
        System.out.println();
        int number = input.nextInt();
        System.out.println("The sum of the digits is " +adder(number));

    }
    public static int adder(int num){
        int length = String.valueOf(num).length();
        int first , last , sum;
        if (length==1){
            return num;
        }
        else
        {
            first = num /10;
            last = num % 10;
            sum = last + adder(first);
        }
        return sum;
    }
}

Answer 6

I see a lot of solutions on here, but not one in which seems as simple as what follows. I've tested it countless times and it works no problem:

public int sumDigits(int n) {
  if (n == 0){
    return 0;
  }
  else{
    return n%10 + sumDigits(n/10);
  }
}