1

我正在实现一个堆栈应用程序，但是每次我将一个项目推送到堆栈上时，我都会收到一个 java.lang.ArrayIndexOutOfBoundsException: 0。

//stack constructor
public Stack() {
    stack = new int[STACKSIZE];
    top = 0;
}


//push code
public void push(int n) throws Exception {
    if(top == STACKSIZE) {
        throw new Exception("Stack Overflow");
    } else {
        stack[top++] = n;
    }
}



//stack size variable
protected int STACKSIZE;

//get stack size
public int getStackSize() {
    return STACKSIZE;
}

//set stack size
public void setStackSize(int size) {
    STACKSIZE = size;
}

//declaring a new stack object in the GUI class
private Stack stack = new Stack();

//variable for default stack size (class level variable)
private int stackSize = 0;

//setting the size
stack.setStackSize(stackSize);

//code where push is being used (located within a jbutton event)
try {
    int size = stack.getStackSize();
    stack.setStackSize(++size);
    String inputNumber = EquationLabel.getText().replaceAll(remove, replaceWith);
    int number = Integer.parseInt(inputNumber);
    clear();
    stack.push(number);
} catch (NumberFormatException error) {
    MessageLabel.setText("Error: " + error.getMessage());
    error.printStackTrace();
} catch (Exception error) {
    MessageLabel.setText("Error: " + error.getMessage());
    error.printStackTrace();
}

//stack trace output
java.lang.ArrayIndexOutOfBoundsException: 0
at Stack.Stack.push(Stack.java:66)
at calculator.Calculator.actionPerformed(Calculator.java:268)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at               javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2713)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
at java.awt.EventQueue.access$000(EventQueue.java:101)
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:680)
at java.awt.EventQueue$4.run(EventQueue.java:678)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

感谢您的任何帮助/指导，我真的不确定这个。

4

3 回答 3

4

您的代码存在多个问题：

  1. 您永远不会初始化变量STACKSIZE。它是一个 int，所以它恰好默认为零。当您第一次初始化存储阵列时，它的值为零。
  2. 您的setStackSize方法更改了STACKSIZE值，但它对内部存储数组没有任何作用（不尝试调整它的大小）。
  3. 无论如何，由于您在构造函数中初始化了一个空数组，因此您永远无法向其中添加任何元素，这就是您得到 ArrayOutOfBoundsException 的原因。

这些都是编码错误，但您也有一些概念性错误。

  1. 您还没有决定是想要一个具有初始固定大小的堆栈，还是一个动态增长的堆栈。因此，您在代码中混合了这两个概念，这会导致错误。

如果您决定使用固定大小的数组，那么您可以将您的类调整为更像这样：

public class Stack {
    private int[] storage;
    private int size;

    public Stack(int capacity) {
        super();
        storage = new int[capacity];
    }

    public void push(int number) {
        if(storage == null) return;
        if(size >= storage.length) throw new RuntimeException("Stack Overflow");

        storage[size] = number;
        ++size;
    }

    public int pop() {
        if(storage == null) throw new RuntimeException("No storage");
        if(size == 0) throw new RuntimeException("Stack Underflow");

        --size;
        return storage[size];
    }
}
于 2012-03-23T04:32:37.280 回答
1

我怀疑问题出在这一行：

stack[top++] = n;

检查为顶部变量传递的值

于 2012-03-23T04:19:20.113 回答
0

stack在您的问题本身中显示变量的创建。无论如何， int stack[]=new int[size];

setStackSize()此外，在函数本身中完成此操作。为此，在类的开头创建数组堆栈并public int stack[];在函数中初始化它，getStackSize如下所示：stack=new int[size];

并且由于您将堆栈的大小增加了 1，这意味着您希望从位置 1 而不是 0 开始堆栈。所以，初始化top=0;。

在 push 函数中它应该是：stack[++top]=n;您应该首先增加 top 的值，然后将项目放在该位置。

于 2012-03-23T04:29:01.323 回答