iOS实现计算器小功能的代码怎么写

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本文利用ios实现计算器app，后期将用mvc结构重构

import UIKitclass 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

增加model文件

import Foundationclass 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 UIKitclass 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        }    }}

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