# About this series

This is series of daily JavaScript coding challenges... for both beginners and advanced users.

Each day I’m gone present you a very simple coding challenge, together with the solution. The solution is intentionally written in a didactic way using classic JavaScript syntax in order to be accessible to coders of all levels.

Solutions are designed with increase level of complexity.

## Today’s coding challenge

```
Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as string.
```

(scroll down for solution)

## Code newbies

If you are a code newbie, try to work on the solution on your own. After you finish it, or if you need help, please consult the provided solution.

## Advanced developers

Please provide alternative solutions in the comments below.

You can solve it using functional concepts or solve it using a different algorithm... or just solve it using the latest ES innovations.

By providing a new solution you can show code newbies different ways to solve the same problem.

## Solution

```
// Solution for challenge30a
var n1 = "2909034221912398942349";
var n2 = "1290923909029309499";
var sum = add(n1, n2);
println(n1, "\n", n2, "\n", sum);
function add(sNumber1, sNumber2)
{
var s = "";
var carry = 0;
var maxSize = Math.max(sNumber1.length, sNumber2.length);
for(var i = 0; i < maxSize; i++)
{
var digit1 = digitFromRight(sNumber1, i);
var digit2 = digitFromRight(sNumber2, i);
var sum = digit1 + digit2 + carry;
var digitSum = sum % 10;
carry = sum >= 10 ? 1 : 0;
s = digitSum.toString() + s;
}
if (carry > 0)
s = carry + s;
return s;
}
function digitFromRight(s, digitNo)
{
if (digitNo >= s.length)
return 0;
var char = s[ s.length - 1 - digitNo ];
return parseInt(char);
}
```

To quickly verify this solution, copy the code above in this coding editor and press "Run".

Note: The solution was originally designed for codeguppy.com environment, and therefore is making use of

`println`

. This is the almost equivalent of`console.log`

in other environments. Please feel free to use your preferred coding playground / environment when implementing your solution.

## Discussion