Program to find covariance

Given a two set of random variable, find Covariance. Covariance is a measure of how much two random variables vary together. It’s similar to variance, but where variance tells you how a single variable varies, covariance tells you how two variables vary together. Covariance can be calculated by using the formula 

Where x' and y' are the means of two given sets.

Examples: 

Input : arr1[] = {65.21, 64.75, 65.26, 65.76, 65.96}
 arr2[] = {67.25, 66.39, 66.12, 65.70, 66.64}
Output : -0.0580511

Input : arr1[] = {5, 20, 40, 80, 100}
 arr2[] = {10, 24, 33, 54, 10}
Output : 187.75

Output: 

-0.0580511

Time Complexity: O(N)
Auxiliary Space: O(1)