Problem Statement

Compute the   Root mean square   of the numbers 1..10.

The   root mean square   is also known by its initials RMS (or rms), and as the quadratic mean. The RMS is calculated as the mean of the squares of the numbers, square-rooted:

Let's start with the solution:

declare
  fun {Square X} X*X end

  fun {RMS Xs}
     {Sqrt
      {Int.toFloat {FoldL {Map Xs Square} Number.'+' 0}}
      /
      {Int.toFloat {Length Xs}}}
  end
in 
  {Show {RMS {List.number 1 10 1}}}