You are given a large integer N. Find the sum of its digits. Eg:- if the integer is 1234, the answer is 1+2+3+4=10. code example

Example 1: To add all the digits of a number till you get a single digit.

#include<bits/stdc++.h> 
using namespace std; 
int digSum(int n) 
{ 
	if (n == 0) 
	return 0; 
	return (n % 9 == 0) ? 9 : (n % 9); 
} 
int main() 
{ 
	int n = 9999; 
	cout<<digSum(n); 
	return 0; 
}

Example 2: Given a long number, return all the possible sum of two digits of it. For example, 12345: all possible sum of two digits from that number are:

function digits(num){
  let numArray = num.toString().split('');
  let sumArray = [];
  
  for (let i = 0; i < numArray.length; i++) {
    for (let j = i+1; j < numArray.length; j++) {
      let sum;
      sum = Number(numArray[i]) + Number(numArray[j]);
      sumArray.push(sum);
    }
  } 
  return sumArray;  
}