Edx - F# - Data and Types

// Learn more about F# at http://fsharp.org
// See the 'F# Tutorial' project for more help.

// The code for both koan and problem are included in this file
// Indented code available at

open System

[<EntryPoint>]
let main argv =

    // Koan

//    let arr = [| 1, 2, 3, 4, 5, 6, 7, 8, 9 |]
//    let l = arr.Length
//    let isEven x = x % 2 = 0
//
//    let out =
//        [ for i = 0 to l do
//              if isEven arr.[i] then yield arr.[i] ]
//
//    let newout = 0 @ out

    let arr = [| 1; 2; 3; 4; 5; 6; 7; 8; 9 |]
    let l = arr.Length
    let isEven x = x % 2 = 0

    let out =
        [ for i = 0 to l - 1 do
              if isEven arr.[i] then yield arr.[i] ]

    let newout = [0] @ out

    printfn "%A" newout

    // Project
    let values = seq {
        let mutable go = true
        while go do
            printf "Enter next number "
            let numberstr = Console.ReadLine()
            let isvalid, number = Double.TryParse(numberstr)
            if not isvalid then
                printfn "Invalid number"
            else
                yield number
            printf "Continue (y/n) "
            let answer = Console.ReadLine()
            go <- answer.ToLower() = "y"
    }
    let fi = (1.0 + Math.Sqrt(5.0)) / 2.0
    let output = [for number in values do yield (number, fi * number)]
    for x in output do
        Console.WriteLine(x)

    Console.ReadKey()
    0 // return an integer exit code