Import java.awt.event. *;
Import javax.swing. *; //Guide package
Class MyClass extends JFrame.
//Create a MyClass class that inherits the window class of the JFrame framework.
//That is to say, all the functions in JFrame can be realized through MyClass.
{
JLabel a 1=new JLabel ("the first number");
//Create a label that displays the first number.
JLabel a2=new JLabel ("the second number");
JLabel a3=new JLabel ("operation result");
JTextField b 1 = new JTextField(5)；
//Create a text box with a default length of 5, which is used to enter the operation number, or it can be blank by default.
JTextField B2 = new JTextField(5)；
JTextField B3 = new JTextField(5)；
//Create a label to display the operation result, or create a label to display the operation result.
JButton a = new JButton(" plus ")；
//Create a button for addition calculation, and add it when clicked.
JButton b = new JButton(" MINUS ")；
JButton c = new JButton(" multiply ")；
JButton d = new JButton(" divide ")；
JPanel jp 1 = new JPanel()； //Create a panel for placing controls.
JPanel jp2 = new JPanel()；
JPanel jp3 = new JPanel()；
MyClass()// constructor, used to initialize.
{
setLayout(new GridLayout(3， 1))； //Add a layout manager with four rows and four columns.
jp 1 . set layout(new FlowLayout())； //Set the JP 1 panel as a streaming layout manager.
jp 1 . set layout(new FlowLayout())；
//Add four controls A 1, B 1, A2 and B2 to the jp 1 panel.
jp 1 . add(a 1)；
jp 1 . add(b 1)；
jp 1 . add(a2)；
jp 1 . add(B2)；
jp 1 . add(a3)；
//Add four controls A, B, C and D to the jp2 panel.
jp2 . add(a)；
jp2 . add(b)；
jp2 . add(c)；
jp2 . add(d)；
jp3 . add(a3)；
jp3 . add(B3)；
//Add three panels JP 1, JP2 and JP3 to the window.
Add (jp1);
Add (JP3);
Add (jp2);
Object e;
A.addActionListener (new ActionListener ())
//Create an anonymous event listener
{
@ Overlay
public void action performed(action event e){
// TODO automatically generated method stub
double x = double . value of(b 1 . gettext()。 toString())；
//Get the first input number and convert it from a string to a double.
double y = double . value of(B2 . gettext()。 toString())；
//Get the second input number and convert it from a string to a double.
B3 . settext("+(x+y))；
//Display the operation result in the text box b3.
}
});
B.addActionListener (new ActionListener ())
{
@ Overlay
public void action performed(action event e){
// TODO automatically generated method stub
double x = double . value of(b 1 . gettext()。 toString())；
double y = double . value of(B2 . gettext()。 toString())；
B3 . settext("+(x-y))；
}
});
C.addactionlistener (newactionlistener ()//Create an anonymous event listener.
{
@ Overlay
public void action performed(action event e){
// TODO automatically generated method stub
double x = double . value of(b 1 . gettext()。 toString())；
double y = double . value of(B2 . gettext()。 toString())；
B3 . settext("+(x * y))；
}
});
D.addactionlistener (newactionlistener ()//Create an anonymous event listener.
{
@ Overlay
public void action performed(action event e){
// TODO automatically generated method stub
double x = double . value of(b 1 . gettext()。 toString())；
double y = double . value of(B2 . gettext()。 toString())；
//Because 0 is not divisible, judgment is needed here.
If (y==0)
{
B3 . settext(" error ")；
}
other
{
B3 . settext("+(x/y))；
}
}
});
//The following are the properties of the setting window.
This.setTitle ("calculator"); //Set the title of the window.
//this.setSize(400，400)； //Set the size of the window, or change it to this.pack ().
this . pack()；
this . setdefaultcloseoperation(DISPOSE _ ON _ CLOSE)； //Set the closing attribute
this . set visible(true)； //Set the visibility of the window
}
Public static void main (string [] args)//main function
{
new my class()；
}
}