抽象类数组

问题描述

为什么我不能实例化一个抽象类，而是创建一个抽象类的数组?

公共抽象类游戏{...}游戏游戏 = 新游戏()；//错误游戏[] gamesArray = 新游戏[10];//没有错误

解决方案

Game[] gamesArray = new Game[10];

实例化意味着创建一个类的实例.在上面的场景中，您刚刚声明了一个 Game 类型的 gamesArray，大小为 10(只是引用，没有别的).这就是为什么它不会抛出任何错误.

尝试执行时会出现错误

gamesArray[0] = new Game();//因为抽象类不能被实例化

但是创建一个抽象类的数组?

以后，你可以做这样的事情

gamesArray[0] = new NonAbstractGame();//其中 NonAbstractGame 扩展了 Games 抽象类.

这是非常允许的，这就是您首先要进入抽象类的原因.

Why can I not instantiate an abstract class but make an array of the abstract class?

public abstract class Game{
  ...
}

Game games = new Game(); //Error
Game[] gamesArray = new Game[10]; //No Error

解决方案

Game[] gamesArray = new Game[10];

Instantiation means creation of an instance of a class. In the above scenario, you've just declared a gamesArray of type Game with the size 10(just the references and nothing else). That's why its not throwing any error.

You'll get the error when you try to do

gamesArray[0] = new Game(); // because abstract class cannot be instantiated

---

Later on, you can do something like this

gamesArray[0] = new NonAbstractGame(); // where NonAbstractGame extends the Games abstract class.

This is very much allowed and this is why you'll be going in for an abstract class on the first place.

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