初階計算機

已經有Auto Layout了

先上動圖：

這次程式碼比較多一點

也有很多可以延伸的功能

//列舉各種算法
enum OperationType{
case add
case subtract
case multiply
case divide
case none
}
class ViewController: UIViewController {
@IBOutlet weak var label: UILabel!
//此變數儲存(運算之前)畫面上的數字 先存入0
var previousNumber:Double = 0
//此變數儲存(當前)畫面上的數字 原始值0 所以存入0
var numberOnScreen:Double = 0
//此變數儲存是不是在運算的過程中 一開始不是所以false
var performingMath = false
//此變數儲存當下是何種運算 一開始都沒有所以none
var operation:OperationType = .none
//此變數來判斷是否重啟運算 把該答案數字直接替換成新輸入的數字
var startNew = true
override var preferredStatusBarStyle: UIStatusBarStyle{
return .lightContent
}
//加法
@IBAction func add(_ sender: UIButton) {
label.text = "+"
operation = .add
//是運算中
performingMath = true
previousNumber = numberOnScreen
}
//減法
@IBAction func subtract(_ sender: UIButton) {
label.text = "-"
operation = .subtract
//是運算中
performingMath = true
previousNumber = numberOnScreen
}
//乘法
@IBAction func multiply(_ sender: UIButton) {
label.text = "x"
operation = .multiply
//是運算中
performingMath = true
previousNumber = numberOnScreen
}
//除法
@IBAction func divide(_ sender: UIButton) {
label.text = "/"
operation = .divide
//是運算中
performingMath = true
previousNumber = numberOnScreen
}
//設定C 清除鍵 且將所有的值回歸初始值
@IBAction func clearC(_ sender: UIButton) {
label.text = "0"
//此變數儲存畫面上的數字 原始值0 所以存入0
numberOnScreen = 0
//此變數儲存畫面運算之前畫面上的數字 先存入0
previousNumber = 0
//此變數儲存是不是在運算的過程中 一開始不是所以false
performingMath = false
//此變數儲存是如何的運算 一開始都沒有所以none
operation = .none
startNew = true
}
//讓文字標籤顯示正確 沒有.0
func makeOKNumberString(from number:Double){
var okText:String
if floor(number) == number{
okText = "\(Int(number))"
}else{
okText = "\(number)"
}
if okText.count >= 10{
//就取前面10個數字
okText = String(okText.prefix(10))
}
label.text = okText
}
@IBAction func giveMeAnswer(_ sender: UIButton) {
//是運算中
if performingMath == true{
switch operation{
case .add:
numberOnScreen = previousNumber + numberOnScreen
makeOKNumberString(from: numberOnScreen)
case .subtract:
numberOnScreen = previousNumber - numberOnScreen
makeOKNumberString(from: numberOnScreen)
case .multiply:
numberOnScreen = previousNumber * numberOnScreen
makeOKNumberString(from: numberOnScreen)
case .divide:
numberOnScreen = previousNumber / numberOnScreen
//驗證該答案數字是不是有小數
makeOKNumberString(from: numberOnScreen)
case .none:
label.text = "0"
}
performingMath = false
startNew = true
}
}
//按到任一數字的方法
@IBAction func numbers(_ sender: UIButton) {
//判斷選到的數字 要-1因為先前有在按鍵Tag設定多1
let inputnumber = sender.tag - 1
if label.text != nil{
if startNew == true{
label.text = "\(inputnumber)"
startNew = false
}else{
if label.text == "0" || label.text == "+" || label.text == "-" || label.text == "x" || label.text == "/"{
label.text = "\(inputnumber)"
}else{
label.text = label.text! + "\(inputnumber)"
}
}
numberOnScreen = Double(label.text!) ?? 0
}
}

passmike/Calculator-