急求java 计算器课程设计报告，有源码，

最新问答

• 闪闪惹人爱ii

  源如下：
  import java.awt.*;
  import java.text.DecimalFormat;
  import java.awt.event.*;
  import javax.swing.*;
  public class Calculator extends JFrame
  {
  private Container container;
  private GridBagLayout layout;
  private GridBagConstraints constraints;
  private JTextField displayField;//计算结果显示区
  DecimalFormat df; //设置输出精度
  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;
  df = new DecimalFormat("0.

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• NightWish431

  ##"); //设置输出精度(对于double型值)
  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);//只显示"-"号,"+"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(""+ df.format(result));
  }
  public static void main(String []args)
  {
  Calculator calculator=new Calculator();
  calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
  }

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