SwiftとXcode6で作るカウンターアプリ

ViewController.swift

import UIKit

class ViewController: UIViewController {

    @IBOutlet var counter: UILabel!
    
    var num:Int = 0
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func updateCounter(num: Int) {
        counter.text = String(num)
    }
    
    @IBAction func plusOne(sender: AnyObject) {
        num += 1
        updateCounter(num)
    }

    @IBAction func minusOne(sender: AnyObject) {
        num -= 1
        updateCounter(num)
    }
    
    @IBAction func resetCounter(sender: AnyObject) {
        num = 0
        updateCounter(num)
    }
    
}