Challenge 2: Calculating the First 'n' Fibonacci Numbers

Problem statement

In this exercise, you have to calculate the first ‘n’ fibonacci numbers. The fibonacci series is:

$$0,1,1,2,3,5,8,13,...........$$

The first two fibonacci numbers are 0 and 1. Every subsequent number in the fibonacci sequence is the sum of the previous two.

You will be given a number n, and your code should store first n fibonacci values in the string fib. You can use the valueOf() method of string to convert int value into a string.