高手帮忙用Java设计个计算器程序！

最新问答

• 宜木构思家具

  import java.awt.*;
  import java.awt.event.*;
  
  public class CalcAppDemo extends Frame{
  private TextField t_result;
  private Panel p_main; //主面板
  private Panel p_num; //数字面板
  private Panel p_oper; //作符面板
  private Panel p_show; //显示面板
  private Button b_num[]; //数字按钮
  private Button b_oper[]; //作符面板
  
  public CalcAppDemo(String title){
  setTitle(title);
  t_result = new TextField("0.0", 21);
  p_main = new Panel();
  p_num = new Panel();
  p_oper = new Panel();
  p_show = new Panel();
  p_main.setLayout(new BorderLayout());
  p_num.setLayout(new GridLayout(4, 3, 1, 1));
  p_oper.setLayout(new GridLayout(4, 2, 1, 1));
  
  b_num = new Button[12];
  for(int i=0; i<9; i++)
  {
  b_num[i] = new Button(new Integer(i+1).toString());
  }
  b_num[9] = new Button("0");
  b_num[10] = new Button("cls");
  b_num[11] = new Button(".");
  for(int i=0; i<12; i++)
  {
  p_num.add(b_num[i]);
  }
  
  b_oper = new Button[8];
  b_oper[0] = new Button("+");
  b_oper[1] = new Button("-");
  b_oper[2] = new Button("*");
  b_oper[3] = new Button("/");
  b_oper[4] = new Button("pow");
  b_oper[5] = new Button("sqrt");
  b_oper[6] = new Button("+/-");
  b_oper[7] = new Button("=");
  for(int i=0; i<8; i++) //
  {
  p_oper.add(b_oper[i]);
  }
  
  t_result.setEditable(false);
  p_show.add(t_result, BorderLayout.NORTH);
  p_main.add(p_show, BorderLayout.NORTH);
  p_main.add(p_num, BorderLayout.WEST);
  p_main.add(p_oper, BorderLayout.EAST);
  this.add(p_main, BorderLayout.CENTER);
  setSize(400, 400);
  setResizable(false);
  pack();
  
  this.addWindowListener(new WindowAdapter(){
  public void windowClosing(WindowEvent e)
  {
  System.exit(0);
  }
  });
  ButtonListener b1 = new ButtonListener();
  for(int i=0; i<12; i++)
  {
  b_num[i].addActionListener(b1);
  }
  for(int i=0; i<8; i++)
  {
  b_oper[i].addActionListener(b1);
  }
  }
  
  class ButtonListener implements ActionListener
  {
  private String lastOp; //存储上一此作符
  private String strVal; //存储数字对应的字符串
  private double total; //总数
  private double number; //存储新输入的数
  private boolean firsttime; //判断是否第一次按下的是作符按钮
  private boolean operatorPressed;//判断是否已经按过作符按钮
  
  ButtonListener()
  {
  firsttime = true;
  strVal = "";
  }
  
  //处理器
  public void actionPerformed(ActionEvent e)
  {
  String s = ((Button)e.getSource()).getLabel().trim();
  
  if(Character.isDigit(s.charAt(0)))
  {//判断是作数还是作符
  handleNumber(s);
  }
  else
  {
  calculate(s);
  }
  }
  
  //判断是一元作符还是二元作符，并根据作符类型做计算
  void calculate(String op)
  {
  operatorPressed = true;
  
  if(firsttime&&! isUnary(op))
  {
  total = getNumberOnDisplay();
  firsttime = false;
  }
  if(isUnary(op))
  {
  handleUnaryOp(op);
  }
  else if(lastOp != null)
  {
  handleBinaryOp(lastOp);
  }
  if(! isUnary(op))
  {
  lastOp = op;
  }
  }
  
  //判断是否一元作符
  boolean isUnary(String s)
  {
  return s.equals("=")
  ||s.equals("cls")||s.equals("sqrt")
  ||s.equals("+/-")||s.equals(".");
  }
  
  //处理一元作符
  void handleUnaryOp(String op)
  {
  if(op.equals("+/-"))
  {//
  number = negate(getNumberOnDisplay() + "");
  t_result.setText("");
  t_result.setText(number + "");
  return;
  }else if(op.equals("."))
  {
  handleDecPoint();
  return;
  }else if(op.equals("sqrt"))
  {
  number = Math.sqrt(getNumberOnDisplay());
  t_result.setText("");
  t_result.setText(number + "");
  return;
  }else if(op.equals("="))
  {//
  if(lastOp!= null && !isUnary(lastOp))
  {
  handleBinaryOp(lastOp);
  }
  lastOp = null;
  firsttime = true;
  return;
  }else
  {
  clear();
  }
  }
  
  //处理二元运算符
  void handleBinaryOp(String op)
  {
  if(op.equals("+"))
  {
  total +=number;
  }else if(op.equals("-"))
  {
  total -=number;
  }else if(op.equals("*"))
  {
  total *=number;
  }else if(op.equals("/"))
  {
  try
  {
  total /=number;
  }catch(ArithmeticException ae){}
  }else if(op.equals("pow"))
  total = Math.pow(total, number);
  //t_result.setText("");
  lastOp = null;
  // strVal = "";
  number = 0;
  t_result.setText(total + "");
  }
  
  //该方法用于处理数字按钮
  void handleNumber(String s)
  {
  if(!operatorPressed)
  {
  strVal += s;
  }else
  {
  operatorPressed = false;
  strVal = s;
  }
  //
  number = new Double(strVal).doubleValue();
  t_result.setText("");
  t_result.setText(strVal);
  }
  
  //该方法用于按下"."按钮
  void handleDecPoint()
  {
  operatorPressed = false;
  //
  if(strVal.indexOf(".")<0)
  {
  strVal += ".";
  }
  t_result.setText("");
  t_result.setText(strVal);
  }
  
  //该方法用于将一个数求反
  double negate(String s)
  {
  operatorPressed = false;
  //如果是一个整数，去掉小数点后面的0
  if(number == (int)number)
  {
  s = s.substring(0,s.indexOf("."));
  }
  
  //如果无"-"增加在该数的前面
  if(s.indexOf("-")<0)
  {
  strVal = "-" + s;
  }
  else
  {
  strVal = s.substring(1);
  }
  return new Double(strVal).doubleValue();
  }
  
  //将显示框中的值转换成Double
  double getNumberOnDisplay()
  {
  return new Double(t_result.getText()).doubleValue();
  }
  
  //清除屏幕并设置所有的标识
  void clear()
  {
  firsttime = true;
  lastOp = null;
  strVal = "";
  total = 0;
  number = 0;
  t_result.setText("0");
  }
  }
  
  public static void main(String[] args) {
  CalcAppDemo c = new CalcAppDemo("简单的计算器程序");
  c.setVisible(true);
  }
  
  }
  参

  浏览 446赞 108时间 2023-09-09
• 武汉碧海蓝天

  import java.awt.*;
  import java.awt.event.*;
  import javax.swing.*;
  
  public class Calculator extends JFrame {
  
  private static final long serialVersionUID = 1L;
  
  private Container container;
  
  private GridBagLayout layout;
  
  private GridBagConstraints constraints;
  
  private JTextField displayField;// 计算结果显示区
  
  private String lastCommand;// 保存+,-,*,/,=命令
  
  private double result;// 保存计算结果
  
  private boolean start;// 判断是否为数字的开始
  
  public Calculator() {
  
  super("Calculator");
  container = getContentPane();
  layout = new GridBagLayout();
  container.setLayout(layout);
  constraints = new GridBagConstraints();
  start = true;
  result = 0;
  lastCommand = "=";
  displayField = new JTextField(20);
  displayField.setHorizontalAlignment(JTextField.RIGHT);
  constraints.gridx = 0;
  constraints.gridy = 0;
  constraints.gridwidth = 4;
  constraints.gridheight = 1;
  constraints.fill = GridBagConstraints.BOTH;
  constraints.weightx = 100;
  constraints.weighty = 100;
  layout.setConstraints(displayField, constraints);
  container.add(displayField);
  ActionListener insert = new InsertAction();
  ActionListener command = new CommandAction();
  addButton("Backspace", 0, 1, 2, 1, insert);
  addButton("CE", 2, 1, 1, 1, insert);
  addButton("C", 3, 1, 1, 1, insert);
  addButton("7", 0, 2, 1, 1, insert);
  addButton("8", 1, 2, 1, 1, insert);
  addButton("9", 2, 2, 1, 1, insert);
  addButton("/", 3, 2, 1, 1, command);
  addButton("4", 0, 3, 1, 1, insert);
  addButton("5", 1, 3, 1, 1, insert);
  addButton("6", 2, 3, 1, 1, insert);
  addButton("*", 3, 3, 1, 1, command);
  addButton("1", 0, 4, 1, 1, insert);
  addButton("2", 1, 4, 1, 1, insert);
  addButton("3", 2, 4, 1, 1, insert);
  addButton("-", 3, 4, 1, 1, command);
  addButton("0", 0, 5, 1, 1, insert);
  addButton("+/-", 1, 5, 1, 1, insert);// 保存"-"负数,"+"没有实用价值
  addButton(".", 2, 5, 1, 1, insert);
  addButton("+", 3, 5, 1, 1, command);
  addButton("=", 0, 6, 4, 1, command);
  setSize(300, 300);
  setVisible(true);
  
  }
  
  private void addButton(String label, int row, int column, int with,
  int height, ActionListener listener) {
  
  JButton button = new JButton(label);
  constraints.gridx = row;
  constraints.gridy = column;
  constraints.gridwidth = with;
  constraints.gridheight = height;
  constraints.fill = GridBagConstraints.BOTH;
  button.addActionListener(listener);
  layout.setConstraints(button, constraints);
  container.add(button);
  }
  
  private class InsertAction implements ActionListener {
  
  public void actionPerformed(ActionEvent event) {
  
  String input = event.getActionCommand();
  if (start) {
  displayField.setText("");
  start = false;
  if (input.equals("+/-"))
  displayField.setText(displayField.getText() + "-");
  }
  
  if (!input.equals("+/-")) {
  if (input.equals("Backspace")) {
  String str = displayField.getText();
  if (str.length() > 0)
  displayField
  .setText(str.substring(0, str.length() - 1));
  } else if (input.equals("CE") || input.equals("C")) {
  displayField.setText("0");
  start = true;
  } else
  displayField.setText(displayField.getText() + input);
  }
  }
  }
  
  private class CommandAction implements ActionListener {
  
  public void actionPerformed(ActionEvent evt) {
  String command = evt.getActionCommand();
  if (start) {
  lastCommand = command;
  } else {
  calculate(Double.parseDouble(displayField.getText()));
  lastCommand = command;
  start = true;
  }
  }
  }
  
  public void calculate(double x) {
  if (lastCommand.equals("+"))
  result += x;
  else if (lastCommand.equals("-"))
  result -= x;
  else if (lastCommand.equals("*"))
  result *= x;
  else if (lastCommand.equals("/"))
  result /= x;
  else if (lastCommand.equals("="))
  result = x;
  displayField.setText("" + result);
  }
  
  public static void main(String[] args) {
  Calculator calculator = new Calculator();
  calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
  
  }
  
  主要考虑到java是面向对象,代希望楼主满意.呵呵

  浏览 386赞 127时间 2022-12-17
• xiaoqiao945

  原来这就叫做编程，密密麻麻啊！

  浏览 374赞 84时间 2022-08-30