Shuffle elements of an Array most efficient way , Fisher Yates shuffle algorithm

Problem:

You are given an array of N elements, shuffle elements of this array in such a way that, occurance of any element at any position is equally likely.

Given:

A rand() function that returns any value between 0.0 to 1.0 randomly and a floor() function that gives significant integer from any given float value.

Soltuion: 

We'll use Fisher Yates Algorithm to solve this problem. you can watch explanation in video.