Write a program that computes the square root of a number using the following iterative algorithm $($not using any in$-$built function$).$

Given a number $a,$ where a $=27,$compute the subsequent guesses of the square root using the following iterative

formula:

$x_{i+1}=\frac{1}{2}(x_i+\frac{a}{x_i})$

That is$,$ you use $i^{th}$ guess to compute the $(i+1{)}^{th}$ guess. Stop when the two guesses are within

${10}^{-6}$