从 'full' 数组中删除元素

Question

这是我正在做的一个小作业。我是初学者 Java 程序员，在这个小程序中遇到了运行问题。由于某种原因，如果数组包含 10 个元素，则删除方法不起作用。我希望 advice/help 能解决这个问题。

当数组包含 10 个元素时，我试图删除一个，textArea 中元素的 ar运行gement 不是它应该的。一切都应该超过1，包含9个元素，最后一个元素为0。当删除一个元素时，所有元素都应该自行调整并向左移动。

输出的默认外观运行ce是：[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

如果我输入数字 1 - 10，输出应该如下所示： [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

如果用户尝试删除最后一个元素，它会将其设置为 0： [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

但是，如果用户试图删除另一个元素，比如说 5，程序会在控制台中抛出越界异常。如果他们删除 5，输出应该是：[1, 2, 3, 4, 6, 7, 8, 9, 10, 0]

有关更多上下文，这里是作业详细信息：

Create a complete program that has the ability to store and display integer values in an array. The maximum number of values that your program should be able to handle is 10.

Add additional elements to the array using screen input (textbox and button).

Remove array elements based on screen input (textbox and button).

List all of the elements in the array and compute the sum of all the elements.

List the even elements in the array and compute the sum of the even elements.

List the odd elements in the array and compute the sum of the odd elements.

    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.util.Arrays;

    public class SumElement implements ActionListener {

    public static JButton add, remove, sumAll, sumEven, sumOdd;
    public static JTextField inputField;
    public static JTextArea textArea;
    public static int counter = 0;
    public static int[] numbers = new int[10];
    public static JLabel titleText;

    public static void main(String[] args) {
        System.out.println("Counter: " + counter);

        // Frame
        JFrame frame = new JFrame("Integer Sums");
        frame.setSize(178, 240);
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Container panel
        JPanel container = new JPanel();
        container.setLayout(new BoxLayout(container, BoxLayout.PAGE_AXIS));
        frame.setContentPane(container);

        // Title panel
        JPanel titlePane = new JPanel();
        titleText = new JLabel("Integer Sums");

        // Content panel
        JPanel content = new JPanel();
        content.setPreferredSize(new Dimension(300, 180));
        content.setLayout(null);

        // Buttons
        add = new JButton("Add");
        add.setBounds(4, 50, 80, 20);
        add.addActionListener(new SumElement());

        remove = new JButton("Remove");
        remove.setBounds(88, 50, 80, 20);
        remove.addActionListener(new SumElement());

        sumAll = new JButton("Sum All");
        sumAll.setBounds(4, 74, 164, 20);
        sumAll.addActionListener(new SumElement());

        sumEven = new JButton("Sum Even");
        sumEven.setBounds(4, 98, 164, 20);
        sumEven.addActionListener(new SumElement());

        sumOdd = new JButton("Sum Odd");
        sumOdd.setBounds(4, 122, 164, 20);
        sumOdd.addActionListener(new SumElement());

        // Text area, and text field
        inputField = new JTextField();
        inputField.setBounds(4, 21, 164, 25);

        JLabel inputLabel = new JLabel("Input integer value below:");
        inputLabel.setBounds(12, 6, 164, 13);

        textArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane(textArea);
        scrollPane.setBounds(4, 144, 165, 36);

        // Adding everything
        container.add(titlePane);
        titlePane.add(titleText);
        container.add(content);
        content.add(inputLabel);
        content.add(inputField);
        content.add(scrollPane);
        content.add(add);
        content.add(remove);
        content.add(sumAll);
        content.add(sumEven);
        content.add(sumOdd);

        // Extras
        frame.toFront();
        frame.setVisible(true);
    }

    public void actionPerformed(ActionEvent event) {
        if (event.getActionCommand().equals("Add")) {
            if (counter == 10) {
                titleText.setText("Error: too many values");
            } else {
                numbers[counter] = Integer.parseInt(inputField.getText());
                textArea.setText(Arrays.toString(numbers));
                counter++;
            }
            System.out.println("Counter: " + counter);
        } else if (event.getActionCommand().equals("Remove")) {
            for (int i = 0; i < counter; i++) {
                if (Integer.parseInt(inputField.getText()) == numbers[i]) {
                    for (int x = i; x < counter - 1; x++) {
                        numbers[x] = numbers[x + 1];
                    }
                    textArea.setText(Arrays.toString(numbers));
                    counter--;
                } else {
                    titleText.setText("Error: value doesn't exist");
                }
            }
            System.out.println("Counter: " + counter);
        } else if (event.getActionCommand().equals("Sum All")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                sum += numbers[i];
            }
            titleText.setText("Sum is " + sum);
        } else if (event.getActionCommand().equals("Sum Even")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                if (numbers[i] % 2 == 0) {
                    sum += numbers[i];
                }
            }
            titleText.setText("Sum of even values is: " + sum);
        } else if (event.getActionCommand().equals("Sum Odd")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                if (numbers[i] % 2 != 0) {
                    sum += numbers[i];
                }
            }
            titleText.setText("Sum of odd values is: " + sum);
        }
    }
}

下面是代码的修改后的 actionPerformed 部分。现在可以删除最后一个数组值。但是，如果数组已满，并且用户试图删除最后一个元素以外的元素，则会抛出错误。我仍然不确定如何修复此错误。

    public void actionPerformed(ActionEvent event) {
        if (event.getActionCommand().equals("Add")) {
            if (counter == 10) {
                titleText.setText("Error: too many values");
            } else {
                numbers[counter] = Integer.parseInt(inputField.getText());
                textArea.setText(Arrays.toString(numbers));
                counter++;
            }
            System.out.println("Counter: " + counter);
        } else if (event.getActionCommand().equals("Remove")) {
            if (Integer.parseInt(inputField.getText()) == numbers[9]) {
                numbers[9] = 0;
                counter--;
                textArea.setText(Arrays.toString(numbers));
            } else {
                for (int i = 0; i < counter; i++) {
                    if (Integer.parseInt(inputField.getText()) == numbers[i]) {
                        for (int x = i; x <= counter - 1; x++) {
                            numbers[x] = numbers[x + 1];
                        }
                        textArea.setText(Arrays.toString(numbers));
                        counter--;
                    }
                }
            }
            System.out.println("Counter: " + counter);
        } else if (event.getActionCommand().equals("Sum All")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                sum += numbers[i];
            }
            titleText.setText("Sum is " + sum);
        } else if (event.getActionCommand().equals("Sum Even")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                if (numbers[i] % 2 == 0) {
                    sum += numbers[i];
                }
            }
            titleText.setText("Sum of even values is: " + sum);
        } else if (event.getActionCommand().equals("Sum Odd")) {
            int sum = 0;
            for (int i = 0; i <= counter; i++) {
                if (numbers[i] % 2 != 0) {
                    sum += numbers[i];
                }
            }
            titleText.setText("Sum of odd values is: " + sum);
        }
    }
}

Answer 1

问题应该出在这段代码中：

for (int x = i; x <= counter - 1; x++) {
    numbers[x] = numbers[x + 1];
}

则数组包含10个元素变量counter为10。在这种情况下，迭代将计算 -1，即 9。在下一行中，您尝试获取“numbers[x + 1]”，即 10[(x=9)+1]，因此超出范围. 如果将它更改为计数器 -2 而不是 -1 它应该可以工作，因为 atm 你从下一个字段中获取元素来填充它应该仍然工作的位置。

Answer 2

下面的代码应该正确删除整数值（如果存在）。但是，它不处理数组中存在多个相同整数值的情况（即数组有 1,1,1,1,1,1,1,0,0,0 并尝试删除 1）。它不会删除所有 1 并在文本框中显示所有 0。

我不确定要求是否在数组中具有唯一值。如果是这种情况，应该更改 add 函数来处理这种情况。

else if (event.getActionCommand().equals("Remove")) {
            boolean removed = false;
            titleText.setText("Integer Sums");
            for (int i = 0; i < counter; i++) {
                if (Integer.parseInt(inputField.getText()) == numbers[i]) {
                    for (int x = i; x < counter; x++) {
                        if (x == 9) {
                            numbers[x] = 0;
                        } else {
                            numbers[x] = numbers[x + 1];
                            numbers[x + 1] =0;
                        }
                    }
                    textArea.setText(Arrays.toString(numbers));
                    counter--;
                    removed = true;
                }               
            }
            if (!removed) {
                titleText.setText("Error: value doesn't exist");
            } 
            System.out.println("Counter: " + counter);
        }

从 'full' 数组中删除元素

Removing elements from a 'full' array

java

arrays

element