lab2\1

// Solution
// Number in List: 4 -> task 5
// In this sample, the goal was to compute the length of the list

// Method 1: Library Function
let sum1 = List.sumBy(fun x -> x*x)

// Method 2: Recursion
let rec sum2 = function
  | []   -> 0
  | h::t -> sum2(t) + h*h

// Method 3: Tail Rec
let sum3 =
  let rec sum3' acc = function
  | [] -> acc
  | h::t -> sum3' (acc + h*h) t
  sum3' 0

let ar = [1..10]
printfn "Example:\nSum1: %i Sum2: %i Sum3: %i" (sum1 ar) (sum2 ar) (sum3 ar)