IOS之计算器实现

﹏ヽ暗。殇╰゛Y 2022-07-16 11:52 206阅读 0赞

本文利用ios实现计算器app，后期将用mvc结构重构

import UIKit
    
    class CalculViewController: UIViewController {
    
        @IBOutlet weak var display: UILabel!
    
        var userIsInTheMiddleOFTypingANumber:Bool=false
    
        @IBAction func appendDigit(sender: UIButton) {
            let digit=sender.currentTitle!
            if userIsInTheMiddleOFTypingANumber {
            display.text=display.text!+digit
            }else{
                display.text=digit
                userIsInTheMiddleOFTypingANumber=true
            }
        }
        var operandstack:Array<Double>=Array<Double>()
    
    
        @IBAction func operate(sender: UIButton) {
            let operation=sender.currentTitle!;
            if userIsInTheMiddleOFTypingANumber {
                enter()
            }
            switch operation {
            case "×":performeOperation{
       $0*$1}
            case "÷":performeOperation{
       $1/$0}
            case "+":performeOperation{
       $0+$1}
            case "-":performeOperation{
       $1-$0}
            case "√":performeOperation{
       sqrt($0)}
            default:
                break
            }
    
        }
    
    //    func multiply(op1:Double,op2:Double) -> Double {
        
    //        return op1*op2;
    //    }
    
        func performeOperation(operation:(Double,Double)->Double){
            if operandstack.count>=2 {
                displayValue=operation(operandstack.removeLast(),operandstack.removeLast())
                enter()
            }
    
        }
    
         private func performeOperation(operation:Double->Double){
            if operandstack.count>=1 {
                displayValue=operation(operandstack.removeLast())
                enter()
            }
    
        }
    
    
    
        @IBAction func enter() {
            userIsInTheMiddleOFTypingANumber=false
            operandstack.append(displayValue)
            print("operandstack=\(operandstack)")
    
    
        }
    
        var displayValue:Double{
            get{
                return NSNumberFormatter().numberFromString(display.text!)!.doubleValue
            }
            set{
                display.text="\(newValue)"
                userIsInTheMiddleOFTypingANumber=false
            }
        }

**知识点如下**

*  计算型属性的setter与getter
 *  swift利用函数作为参数
 *  swift的重载，详情参见：[swift override][]

**效果如下**

![p1.png][]

**增加model文件**

import Foundation
    
    class CalculatorBrain {
        
        private enum Op : CustomStringConvertible{
            case operand(Double)
            case UnaryOperation(String,Double->Double)
            case BinaryOperation(String,(Double,Double)->Double)
    
            var description:String{
                get{
                    switch self {
                    case .operand(let operand):
                        return "\(operand)"
                    case .BinaryOperation(let symbol,_):
                        return symbol
                    case .UnaryOperation(let symbol, _):
                        return symbol
    
                    }
                }
    
            }
    
        }
    
        private var opstack=[Op]()
        private var knowOps=[String:Op]()
    
        init(){
            func learnOp(op:Op){
                knowOps[op.description]=op
            }
            learnOp(Op.BinaryOperation("×"){$0*$1})
            learnOp(Op.BinaryOperation("÷"){$1/$0})
            learnOp(Op.BinaryOperation("+"){$0+$1})
            learnOp(Op.BinaryOperation("-"){$1-$0})
            learnOp(Op.UnaryOperation("√"){sqrt($0)})
    //        knowOps["×"]=Op.BinaryOperation("×"){
        $0*$1}
    //        knowOps["÷"]=Op.BinaryOperation("÷"){
        $1/$0}
    //        knowOps["+"]=Op.BinaryOperation("+"){
        $0+$1}
    //        knowOps["-"]=Op.BinaryOperation("-"){
        $1-$0}
    //        knowOps["√"]=Op.UnaryOperation("√"){
        sqrt($0)}
        }
    
        private func evaluate(ops:[Op])->(result:Double?,remainOps:[Op]){
            if !ops.isEmpty {
                var remainOps=ops;
                let op=remainOps.removeLast()
                switch op {
                case Op.operand(let operand):
                    return(operand,remainOps)
                case Op.UnaryOperation(_, let operation):
                    let operandEvalution=evaluate(remainOps)
                    if let operand=operandEvalution.result{
                        return(operation(operand),operandEvalution.remainOps)
                    }
                case Op.BinaryOperation(_, let operation):
                    let operandEvlution1=evaluate(remainOps)
                    if let operand1=operandEvlution1.result {
                        let operandEvlution2=evaluate(operandEvlution1.remainOps)
                        if let operand2=operandEvlution2.result {
                            return (operation(operand1,operand2),operandEvlution2.remainOps)
                        }
                    }
    
                }
            }
    
            return (nil,ops)
        }
    
        func evaluate()->Double?{
            let (result,remainder)=evaluate(opstack)
            print("\(opstack)=\(result)with\(remainder)left over")
            return result
        }
    
    
        func pushOperand(operand:Double)->Double?{
            opstack.append(Op.operand(operand))
            return evaluate()
        }
    
        func performOperation(symbol:String)->Double?{
            if let operation=knowOps[symbol]{
                opstack.append(operation)
            }
    
            return evaluate()
    
        }
    
    }

controll修改为

import UIKit
    
    class CalculViewController: UIViewController {
    
        @IBOutlet weak var display: UILabel!
    
        var userIsInTheMiddleOFTypingANumber:Bool=false
        var brain=CalculatorBrain()
    
        @IBAction func appendDigit(sender: UIButton) {
            let digit=sender.currentTitle!
            if userIsInTheMiddleOFTypingANumber {
            display.text=display.text!+digit
            }else{
                display.text=digit
                userIsInTheMiddleOFTypingANumber=true
            }
        }
        //var operandstack:Array<Double>=Array<Double>()
    
    
        @IBAction func operate(sender: UIButton) {
    
            if userIsInTheMiddleOFTypingANumber {
                enter()
            }
            if let operation=sender.currentTitle{
                if let result=brain.performOperation(operation) {
                    displayValue=result
                }else{
                    displayValue=0
                }
            }
    
        }
    
    
    
        @IBAction func enter() {
            userIsInTheMiddleOFTypingANumber=false
            if let result=brain.pushOperand(displayValue){
                displayValue=result
            }else{
                displayValue=0
            }
    
    
        }
    
        var displayValue:Double{
            get{
                return NSNumberFormatter().numberFromString(display.text!)!.doubleValue
            }
            set{
                display.text="\(newValue)"
                userIsInTheMiddleOFTypingANumber=false
            }
        }
    
    
    }

[swift override]: http://stackoverflow.com/questions/29457720/compiler-error-method-with-objective-c-selector-conflicts-with-previous-declara
[p1.png]: /images/20220716/72eba0626bca46188ac16ae909a4a3e2.png