Program to add all digits of a number in Go (Golang)

Overview

The objective is to repeatedly add all digits of a number until the result is only a single digit.

For example

Input: 453
Step 1: 4+5+3 = 12
Step 2: 1+2 =3

Output: 3

Another example

Input: 45
Step 1: 4+5 = 9

Output: 9

Program

Here is the program for the same

package main

import "fmt"

func addDigits(num int) int {

	if num < 10 {
		return num
	}

	for num > 9 {
		num = sum(num)
	}

	return num

}

func sum(num int) int {
	output := 0
	for num > 0 {
		output = output + num%10
		num = num / 10
	}
	return output
}

func main() {
	output := addDigits(453)
	fmt.Println(output)

	output = addDigits(45)
	fmt.Println(output)

}

Output

3
9

Note: Check out our Golang Advanced Tutorial. The tutorials in this series are elaborative and we have tried to cover all concepts with examples. This tutorial is for those who are looking to gain expertise and a solid understanding of golang – Golang Advance Tutorial

Also if you are interested in understanding how all design patterns can be implemented in Golang. If yes, then this post is for you –All Design Patterns Golang