7.Xcode for Swift

Xcode

IDE(Integrated Development Environment)集成开发环境

ViewController.swift

import Cocoa

class ViewController: NSViewController {
	//"!"为隐式封拆的可选类型，至关于告诉编译器，在该变量为nil时毫不会访问它
	@IBOutlet weak var loanAmountField :NSTextField!
	@IBOutlet weak var interestRateField : NSTextField!
	@IBOutlet weak var yearsField : NSTextField!
	@IBOutlet weak var resultsField : NSTextField!
	var simpleInterestCalculator : SimpInterest = SimpInterest()
	
	override func viewDidLoad() {
		super.viewDidLoad()

		// Do any additional setup after loading the view.
	}

	override var representedObject: Any? {
		didSet {
		// Update the view, if already loaded.
		}
	}
	[@IBAction](https://my.oschina.net/u/866341) func buttonClicked(sender : NSButton){
		var result : Double
		result = simpleInterestCalculator.calculate(loanAmount: loanAmountField.doubleValue, interestRate: interestRateField.doubleValue , years: yearsField.integerValue)
		self.resultsField.stringValue = result.description//description让类可以返回其数据的String表示
		
	}


}

SimpInterest.swift

import Foundation


class SimpInterest{
	func calculate(loanAmount : Double ,interestRate :Double,years : Int) -> Double{
		let interestRate1 = loanAmount / 100.0
		let interest = Double(years) * interestRate1 * interestRate//单利计算
		return interestRate + interest
	
	}

}