Fizz Buzz (iOS版)

#SwiftでFizz Buzzを作った時の話
SwiftでFizz Buzzを作りました。
普段Swiftを使う機会が少ないので、間違った記述をしているかもしれません。
またQiita初投稿となるので、その点も含めてご指摘いただければと思います。

##ソースコード
```ViewController.swift
/**********************************************************
  project FizzBuzzApp
  file    ViewController.swift
  date    2017.08.20
**********************************************************/

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var lblCom: UILabel!
    @IBOutlet weak var lblYou: UILabel!
    @IBOutlet weak var btnOther: UIButton!
    @IBOutlet weak var btnFizz: UIButton!
    @IBOutlet weak var btnBuzz: UIButton!
    @IBOutlet weak var btnFizzBuzz: UIButton!
    @IBOutlet weak var btnRestart: UIButton!
    
    var num: Int = 0
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        num = 0;
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    
  
    @IBAction func OtherTouch(_ sender: Any) {
        //otherボタンタッチ時の処理
        //ボタンのキャプションを変更する処理を実装する予定
        num = num + 1
        lblYou.text = num.description
        var hoge = decisionYou(input: num)
        if hoge == false {
            dispAlert()
        }
        var dispStr = computer()
        lblCom.text = dispStr
    }
    
    
    @IBAction func FizzTouch(_ sender: Any) {
        //fizzボタンタッチ時の処理
        num = num + 1
        lblYou.text = "Fizz"
        var hoge = decisionYou(input: -1)
        if hoge == false {
            dispAlert()
        }
        var dispStr = computer()
        lblCom.text = dispStr
    }

    @IBAction func BuzzTouch(_ sender: Any) {
        //buzzボタンタッチ時の処理
        num = num + 1
        lblYou.text = "Buzz"
        var hoge = decisionYou(input: -2)
        if hoge == false {
            dispAlert()
        }
        var dispStr = computer()
        lblCom.text = dispStr
    }
   

    @IBAction func FizzBuzzTouch(_ sender: Any) {
        //fizzbuzzボタンタッチ時の処理
        num = num + 1
        lblYou.text = "Fizz Buzz"
        var hoge = decisionYou(input: -3)
        if hoge == false {
            dispAlert()
        }
        var dispStr = computer()
        lblCom.text = dispStr
    }
    
    @IBAction func RestartTouch(_ sender: Any) {
        num = 0
        lblCom.text = ""
        lblYou.text = ""
    }
    
    
    /**********************************************************
     function  decisionYou
     brief     Decisioned user input
     param     (input)     User input by button
     return    (decision)  Decisioned result

     **********************************************************/
    
    func decisionYou(input:Int) -> Bool {
        //判定処理
        var decision: Bool?   //decisionがfalseでアウト
        if input > 0 {
            if (input % 15) == 0 {
                decision = false
            }else if(input % 5) == 0 {
                decision = false
            }else if(input % 3) == 0 {
                decision = false
            }else{
                decision = true
            }
        }else{
            switch input {
            case -1:
                if (num % 3) == 0 {
                    decision = true
                }else{
                    decision = false
                }
                break
                
            case -2:
                if (num % 5) == 0 {
                    decision = true
                }else{
                    decision = false
                }
                break
                
            case -3:
                if (num % 15) == 0 {
                    decision = true
                }else{
                    decision = false
                }

                break
                
            default:
                break
            }
            
        }
        return decision!
    }
    
    /**********************************************************
     function  dispAlert
     brief     Displayed AlertView
     param     none
     return    none
    **********************************************************/
    func dispAlert() {
        let alert: UIAlertController = UIAlertController(title: "Message", message: "Miss", preferredStyle: UIAlertControllerStyle.alert)
        let defaultAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {(action: UIAlertAction!) -> Void in
            print("OK")
        })
        alert.addAction(defaultAction)
        present(alert, animated: true, completion: nil)
    }
    
    /**********************************************************
     function  computer
     brief     computer logic
     param     none
     return    (dispStr)   Display strings
     **********************************************************/
    func computer() -> String {
        var dispStr: String
        num = num + 1
        if num % 15 == 0{
            dispStr = "Fizz Buzz"
        }else if num % 5 == 0 {
            dispStr = "Buzz"
        }else if num % 3 == 0{
            dispStr = "Fizz"
        }else{
            dispStr = num.description
        }
        return dispStr
    }
  
}


```