edx_person_classifier.fs

open System

let getUserInput message predicate =
    let mutable loop = true
    let mutable userInput = "";
    while loop do
      printf "%s" message;
      userInput <- Console.ReadLine();
      let isValid = predicate(userInput)
      if isValid = true then loop <- false
      else
        Console.WriteLine("Input was not in the correct format")
    userInput
    

let isNumber str =
  let valid, number = Int32.TryParse str
  valid
let isString str = 
   let result = String.IsNullOrWhiteSpace str
   not result

let displayResult name age =
  if age >= 20 then
    printfn "%s is no longer a kid" name
  elif age > 13 && age < 20 then
    printfn "%s is a teenager" name
  else
    printfn "%s is a kid" name

[<EntryPoint>]
let main argv = 
  let name = getUserInput "Please enter the person's name: " isString
  let ageStr = getUserInput "Please enter the person's age: " isNumber
  let age = Int32.Parse ageStr
  displayResult name age 
  

  0 // return an integer exit code