Question

我正在尝试创建一个整数值的数组列表并运行一些基本的数学运算，如下所示。

int dice1 = 4;
int dice2 = 3;
int dice3 = 6;
int dice4 = 4;
int dice 5 = 5;

ArrayList numbers = new  ArrayList();
        numbers[4] = dice5;
        numbers[3] = dice4;
        numbers[2] = dice3;
        numbers[1] = dice2;
        numbers[0] = dice1;

numbers[3] = numbers[3] * numbers[2];

但是，计算机不允许我这样做并产生错误“运算符”*“不能应用于'对象'和'对象'类型的操作数”。我该如何解决？我认为我必须将数组列表定义为整数数组...但是我不太确定。请保持答案简单，因为我对C＃unity来说很陌生。

谢谢！

Answer 1

ArrayList将所有内容存储为“对象”，基本上是C＃中最基本的类型。你有几个选择。如果你想继续使用ArrayList，那么你需要做你正在成倍增加的东西，比如：

numbers[3] = ((int)numbers[3]) * ((int)numbers[2])

或者，您可以抛弃ArrayList并使用更现代的List＆lt;＆gt;类型。您需要将using System.Collections.Generic添加到顶部，然后您的代码将如下：

int dice1 = 4;
int dice2 = 3;
int dice3 = 6;
int dice4 = 4;
int dice5 = 5;

List<int> numbers = new List<int>(); //List contains ints only
    numbers[4] = dice5;
    numbers[3] = dice4;
    numbers[2] = dice3;
    numbers[1] = dice2;
    numbers[0] = dice1;

numbers[3] = numbers[3] * numbers[2]; //Works as expected

最后，如果你知道你的收藏只有一定数量的东西，你可以使用数组。您的代码现在将是：

int dice1 = 4;
int dice2 = 3;
int dice3 = 6;
int dice4 = 4;
int dice5 = 5;

int[] numbers = new int[5]; //Creates an int array with 5 elements
//Meaning you can only access numbers[0] to numbers[4] inclusive
    numbers[4] = dice5;
    numbers[3] = dice4;
    numbers[2] = dice3;
    numbers[1] = dice2;
    numbers[0] = dice1;

numbers[3] = numbers[3] * numbers[2]; //Works as expected

Answer 2

避免使用数组列表

使用List<int>或int[]

然后输入包含的对象而不是对象

Answer 3

您可以在一行中完成：

public class Animation implements Runnable {
    
    private volatile boolean running;
    
    private final SolarSystemGUI frame;
    
    private final SolarSystemModel model;

    public Animation(SolarSystemGUI frame, SolarSystemModel model) {
        this.frame = frame;
        this.model = model;
        this.running = true;
    }

    @Override
    public void run() {
        sleep(5000L);
        long duration = 1000L / model.getFramesPerSecond();
        
        while (running) {
            List<Body> bodies = model.getBodies();
            Point center = null;
            for (Body body : bodies) {
                if (center != null) {
                    body.setCenter(center);
                }
                center = body.getOrbitPoint();
            }
            repaint();
            sleep(duration);
        }
    }
    
    private void sleep(long duration) {
        try {
            Thread.sleep(duration);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    private void repaint() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                frame.repaint();
            }
        });
    }

    public synchronized void setRunning(boolean running) {
        this.running = running;
    }
    
}

Answer 4

您需要将对象解析为字符串，然后解析为int值，然后将其与*运算符配合使用。但是，您首先必须使用空值初始化arraylist，然后分配数字值，这样，使用以下代码，我为您做了明确的更改。

int dice1 = 4;
    int dice2 = 3;
    int dice3 = 6;
    int dice4 = 4;
    int dice5 = 5;
    int capacity=5;
    ArrayList numbers = new ArrayList(capacity);
    for (int i = 0; i < capacity;i++ )
    {
        numbers.Add(null);
    }
    numbers[4] = dice5;
    numbers[3] = dice4;
    numbers[2] = dice3;
    numbers[1] = dice2;
    numbers[0] = dice1;

    numbers[3] = (int.Parse(numbers[3].ToString()) * int.Parse(numbers[2].ToString()));
    print(numbers[3]);

在c＃unity中定义数组列表。

4 个答案: