摘要：
1.类的继承 class Animal { func breathe(){ //... } } class Cat: Animal{ var hasHair = true } let cat = Cat() cat.breathe() cat.hasHai class SmallCat: Cat{ 阅读全文
摘要：
1.根据用户回答计算得分 ViewController.swift: import UIKit class ViewController: UIViewController { var questionIndex = 0 var score = 0 @IBOutlet weak var questi 阅读全文