java 简单的计算器程序实例代码
java简单的计算器程序
实现实例：
importjava.awt.*;
importjava.awt.event.*;
importjavax.swing.*;
publicclassCalculator
{
publicstaticvoidmain(String[]args)
{
EventQueue.invokeLater(newRunnable()
{
publicvoidrun()
{
CalculatorFrameframe=newCalculatorFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
/**
*Aframewithacalculatorpanel.
*/
classCalculatorFrameextendsJFrame
{
publicCalculatorFrame()
{
setTitle("Calculator");
CalculatorPanelpanel=newCalculatorPanel();
add(panel);
pack();
}
}
classCalculatorPanelextendsJPanel
{
privateJButtondisplay;
privateJPanelpanel;
privatedoubleresult;
privateStringlastCommand;
privatebooleanstart;
publicCalculatorPanel()
{
setLayout(newBorderLayout());
result=0;
lastCommand="=";
start=true;
//addthedisplay
display=newJButton("0");
display.setEnabled(false);
add(display,BorderLayout.NORTH);
ActionListenerinsert=newInsertAction();
ActionListenercommand=newCommandAction();
panel=newJPanel();
panel.setLayout(newGridLayout(4,4));
addButton("7",insert);
addButton("8",insert);
addButton("9",insert);
addButton("/",command);
addButton("4",insert);
addButton("5",insert);
addButton("6",insert);
addButton("*",command);
addButton("1",insert);
addButton("2",insert);
addButton("3",insert);
addButton("-",command);
addButton("0",insert);
addButton(".",insert);
addButton("=",command);
addButton("+",command);
add(panel,BorderLayout.CENTER);
}
privatevoidaddButton(Stringlabel,ActionListenerlistener)
{
JButtonbutton=newJButton(label);
button.addActionListener(listener);
panel.add(button);
}
/**
*Thisactioninsertsthebuttonactionstringtotheendofthedisplaytext.
*/
privateclassInsertActionimplementsActionListener
{
publicvoidactionPerformed(ActionEventevent)
{
Stringinput=event.getActionCommand();
if(start)
{
display.setText("");
start=false;
}
display.setText(display.getText()+input);
}
}
/**
*Thisactionexecutesthecommandthatthebuttonactionstringdenotes.
*/
privateclassCommandActionimplementsActionListener
{
publicvoidactionPerformed(ActionEventevent)
{
Stringcommand=event.getActionCommand();
if(start)
{
if(command.equals("-"))
{
display.setText(command);
start=false;
}
elselastCommand=command;
}else{
calculate(Double.parseDouble(display.getText()));
lastCommand=command;
start=true;
}
}
}
/**
*Carriesoutthependingcalculation.
*@paramxthevaluetobeaccumulatedwiththepriorresult.
*/
publicvoidcalculate(doublex)
{
if(lastCommand.equals("+"))result+=x;
elseif(lastCommand.equals("-"))result-=x;
elseif(lastCommand.equals("*"))result*=x;
elseif(lastCommand.equals("/"))result/=x;
elseif(lastCommand.equals("="))result=x;
display.setText(""+result);
}
}
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