java计算器如何实现运算_java 编写计算器 怎样实现连续运算？

要实现一个简单的 Java 计算器，可以使用 Java Swing 来创建一个用户界面，并使用 Java 的算术运算符来执行基本的数学运算。下面是一个简单的示例代码：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame implements ActionListener {

  private JTextField textField;
  private JButton[] buttons;
  private String[] buttonLabels = {
    "7", "8", "9", "+",
    "4", "5", "6", "-",
    "1", "2", "3", "*",
    "0", ".", "=", "/"
  };
  private double num1, num2, result;
  private String operator = "";

  public Calculator() {
    super("Calculator");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel panel = new JPanel(new BorderLayout());
    textField = new JTextField(15);
    textField.setEditable(false);
    panel.add(textField, BorderLayout.NORTH);

    JPanel buttonPanel = new JPanel(new GridLayout(4, 4));
    buttons = new JButton[16];
    for (int i = 0; i < 16; i++) {
      buttons[i] = new JButton(buttonLabels[i]);
      buttons[i].addActionListener(this);
      buttonPanel.add(buttons[i]);
    }
    panel.add(buttonPanel, BorderLayout.CENTER);

    getContentPane().add(panel);
    pack();
    setVisible(true);
  }

  public static void main(String[] args) {
    new Calculator();
  }

  public void actionPerformed(ActionEvent e) {
    String label = e.getActionCommand();

    if (label.equals("C")) {
      textField.setText("");
    } else if (label.equals("=")) {
      num2 = Double.parseDouble(textField.getText());
      if (operator.equals("+")) {
        result = num1 + num2;
      } else if (operator.equals("-")) {
        result = num1 - num2;
      } else if (operator.equals("*")) {
        result = num1 * num2;
      } else if (operator.equals("/")) {
        result = num1 / num2;
      }
      textField.setText("" + result);
      num1 = result;
      operator = "";
    } else if (label.equals("+") || label.equals("-") || label.equals("*") || label.equals("/")) {
      num1 = Double.parseDouble(textField.getText());
      operator = label;
      textField.setText("");
    } else {
      textField.setText(textField.getText() + label);
    }
  }
}

这个计算器可以进行基本的加、减、乘、除运算。要实现连续运算，可以在等号按钮的事件处理程序中将运算结果存储到 num1 变量中，并清空操作符变量 operator，以便进行下一次运算。例如：

else if (label.equals("=")) {
  num2 = Double.parseDouble(textField.getText());
  if (operator.equals("+")) {
    result = num1 + num2;
  } else if (operator.equals("-")) {
    result = num1 - num2;
  } else if (operator.equals("*")) {
    result = num1 * num2;
  } else if (operator.equals("/")) {
    result = num1 / num2;
  }
  textField.setText("" + result);
  num1 = result;
  operator = "";
}

这样，用户就可以在计算器上进行连续的数学运算。