计算器所需求功能
1. 加减乘除
2. 开平方
3. 开次方
4. 能进行正负转换
计算器所用模式：MVC
计算器所用语言：Swift
计算器所参考课程：斯坦福
第一步：构造计算器界面
image.png
第二步：连接事件
显示器Lable连接Outlet
@IBOutlet weak var display: UILabel!
var userIsInTheMiddleOfTyping = false
数字按钮Botton连接第一个Action
@IBAction func touchDight(_ sender: UIButton) {
let dight = sender.currentTitle!
if userIsInTheMiddleOfTyping {
let textCurrentlyInDisplay = display.text!
display.text = textCurrentlyInDisplay + dight
} else{
display.text = dight
userIsInTheMiddleOfTyping = true
}
}
var displayValue: Double{
get {
return Double(display.text!)!
}
set{
display.text = String(newValue)
}
}
运算符号Botton连接第二个Action
@IBAction func performOperation(_ sender: UIButton) {
if userIsInTheMiddleOfTyping{
brain.setOperand(displayValue)
userIsInTheMiddleOfTyping = false
}
if let mathematicalSymbol = sender.currentTitle{
brain.performOperation(mathematicalSymbol)
}
if let result = brain.result{
displayValue = result
}
}
AC清屏按钮Botton连接第三个Action
@IBAction func AC(_ sender: UIButton) {
display.text = “ “;
}
private var brain = CalculatorBrain()
第三步：写计算器的运算部分
定义一个枚举
private enum Operation{
case constant(Double)
case unaryOperation((Double) -> Double)
case binaryOperation((Double,Double) -> Double)
case equals
}
声明一个字典
private var operations:
Dictionary = [
"V" : Operation.unaryOperation({sqrt($0)}),
"∛" : Operation.unaryOperation({pow($0, 1/3)}),
"±" : Operation.unaryOperation({ -$0 }),
"+" : Operation.binaryOperation({ $0 + $1 }),
"-" : Operation.binaryOperation({ $0 - $1 }),
"x" : Operation.binaryOperation({ $0 * $1 }),
"/" : Operation.binaryOperation({ $0 / $1 }),
"=" : Operation.equals
]
- Swift中编译器自动给参数定义了一个参数$0,第二个参数$1
计算器需要进行二元运算
let function: (Double,Double) -> Double
let firstOperand: Double
func perform(with secondOperand: Double) -> Double{
return function(firstOperand , secondOperand )
}
}
计算器逻辑
mutating func performOperation(_ symbol: String){
if let operation = operations[symbol] {
switch operation{
case.constant(let Value):
accumulator = Value
case.unaryOperation(let function) :
if accumulator != nil{
accumulator = function(accumulator!)
}
case.binaryOperation(let function):
if accumulator != nil {
pbo = PendingBinaryOperation(function: function ,firstOperand: accumulator!)
accumulator = nil
}
case.equals:
performPendingBinaryOperation()
}
}
}
private mutating func performPendingBinaryOperation(){
if pbo != nil && accumulator != nil {
accumulator = pbo!.perform(with: accumulator!)
pbo = nil
}
}
private var pbo: PendingBinaryOperation?
第四步：启动页
image.png
第五步：应用图标
制作不同像素的图片进行添加
image.png
代码部分
ViewController.swift
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var display: UILabel!
var userIsInTheMiddleOfTyping = false
@IBAction func touchDight(_ sender: UIButton) {
let dight = sender.currentTitle!
if userIsInTheMiddleOfTyping {
let textCurrentlyInDisplay = display.text!
display.text = textCurrentlyInDisplay + dight
} else{
display.text = dight
userIsInTheMiddleOfTyping = true
}
}
var displayValue: Double{
get {
return Double(display.text!)!
}
set{
display.text = String(newValue)
}
}
@IBAction func AC(_ sender: UIButton) {
display.text = “ “;
}
private var brain = CalculatorBrain()
@IBAction func performOperation(_ sender: UIButton) {
if userIsInTheMiddleOfTyping{
brain.setOperand(displayValue)
userIsInTheMiddleOfTyping = false
}
if let mathematicalSymbol = sender.currentTitle{
brain.performOperation(mathematicalSymbol)
}
if let result = brain.result{
displayValue = result
}
}
}
CalculatorBrain.swift
import Foundation
struct CalculatorBrain {
private var accumulator: Double?
private enum Operation{
case constant(Double)
case unaryOperation((Double) -> Double)
case binaryOperation((Double,Double) -> Double)
case equals
}
private var operations: Dictionary = [
"V" : Operation.unaryOperation({sqrt($0)}),
"∛" : Operation.unaryOperation({pow($0, 1/3)}),
"±" : Operation.unaryOperation({ -$0 }),
"+" : Operation.binaryOperation({ $0 + $1 }),
"-" : Operation.binaryOperation({ $0 - $1 }),
"x" : Operation.binaryOperation({ $0 * $1 }),
"/" : Operation.binaryOperation({ $0 / $1 }),
"=" : Operation.equals
]
mutating func performOperation(_ symbol: String){
if let operation = operations[symbol] {
switch operation{
case.constant(let Value):
accumulator = Value
case.unaryOperation(let function) :
if accumulator != nil{
accumulator = function(accumulator!)
}
case.binaryOperation(let function):
if accumulator != nil {
pbo = PendingBinaryOperation(function: function ,firstOperand: accumulator!)
accumulator = nil
}
case.equals:
performPendingBinaryOperation()
}
}
}
private mutating func performPendingBinaryOperation(){
if pbo != nil && accumulator != nil {
accumulator = pbo!.perform(with: accumulator!)
pbo = nil
}
}
private var pbo: PendingBinaryOperation?
private struct PendingBinaryOperation{
let function: (Double,Double) -> Double
let firstOperand: Double
func perform(with secondOperand: Double) -> Double{
return function(firstOperand , secondOperand )
}
}
mutating func setOperand(_ operand: Double){
accumulator = operand
}
var result: Double? {
get {
return accumulator
}
}
}