Import java.awt.event. *;
Import javax.swing. *;
Public class calculator implements ActionListener{
Private double data 1=0.0, data2 = 0.0.
Private string t _ content
Boolean number = false;
//key is used to indicate the button pressed by the user, that is, addition, subtraction, multiplication and division.
//key is 0 for+,1 for-,2 for *, and/
Shortcut key =-1;
The value of //pkey is-1~5.
//pkey is-1, indicating that the = key is pressed for the first time, and pkey is 5, indicating that it is not the first time to press the = key.
//When //pkey is 0, 1, 2,3, it means+,-,*,/
short pkey =- 1；
Frame frame = new frame ("calculator"); //Define a form titled Calculator
TextField TextField = new TextField(30)； //Define a computer
//Define the Backspace, ce and c0 buttons.
Button Backspace = New button ("Backspace");
Button ce = new button ("CE");
Button c0 = New button ("c");
//Define the panel, in which the backspace, ce, c0 buttons and the computer blue textfeild are placed in the panel p 1.
//The remaining buttons are placed on panel p2.
Panel p 1 = new Panel()；
Panel p2 = new Panel()；
//Define the button array on the interface, that is, all buttons except Backspace, ce and C0 buttons.
String name []={"7 ","8 ","9 ","0 ","sqrt ","4 ","5 ","6 ","* ",","1", "2", "3", "
Button bb[]= new button [names.length];
Public static void main(String[] args){
Calculator cal = new calculator ();
cal . go()；
}
Public void go(){
frame.setSize(300，200)；
frame . set layout(new BorderLayout())；
Font fonts = new font ("italics _ GB 23 12", font.plain,12); //The first page
//Set the font and layout management type of the panel p 1, and add the textfeild object to the panel.
P 1.setFont (font);
P 1.setLayout (new GridLayout(2, 1 0, 5,10));
Textfield.setFont (font);
p 1.add(textfield，null)；
//backspace, ce, c0 button to register the addActionListener method.
backspace . addactionlistener(this)；
ce . addactionlistener(this)；
c0 . addactionlistener(this)；
//Add Backspace, ce and c0 buttons to the p 1 panel.
P 1.add (backspace, empty);
p 1.add(ce，null)；
p 1.add(c0，null)；
//Set the layout manager type of panel p2 to GridLayout.
p2.setLayout(new GridLayout(4，5，5，5))；
//Register the addActionListener method for the buttons in the button group.
for(int I = 0； I< name. length; i++){
Bb[I]= new button (name [i]);
p2 . add(bb[I])；
bb[i]。 addActionListener(this)；
}
//Set the position of panel p 1 and panel p2 in the form.
//Panel p 1 is in the north direction of the form, and Panel p2 is in the south direction of the form.
frame.add(p 1，BorderLayout。 North);
frame.add(p2，BorderLayout。 South);
frame . set visible(true)；
//Click the Close button to exit the system.
frame . addwindowlistener(new window adapter(){
public void window closing(window event e){
system . exit(0)；
}
});
}
public void action performed(action event AE){
String s;
//Use the getActionCommand () method of the ActionEvent class to find out which button triggered the operation. //Page 2
s = AE . getactioncommand()；
//When the user clicks once, a character will be deleted from the calculated column.
//Clear the characters in the calculation bar first, and then add a string other than Best.
If(s.equals ("backspace") & number) {
t _ content = textfield . gettext()；
textfield . settext(" ")；
for(int I = 0； I<T _ content.length ()-1; i++){
char c = t _ content . charat(I)；
textfield . settext(textfield . gettext()+c)；
}
}
//The user clicks the CE button, and the calculation field is empty.
if(s.equals("CE")){
textfield . settext(" ")；
Number = false;
}
//The user clicked the c button.
if(s . equals(" C "){
textfield . settext(" ")；
data 1 = data 2 = 0.0；
Number = false;
}
//The user clicks the sqrt button, and the negative number cannot be squared.
if(s . equals(" sqrt ")& amp； & code) {
t _ content = textfield . gettext()；
if(t _ content . charat(0)= '-'){
Textfield.setText ("negative numbers cannot be squared");
Number = false;
} Otherwise {
textfield . settext(double . tostring(Java . lang . math . sqrt(double . parse double(t _ content))))；
}
}
//The user clicks the 1/x countdown button, and the denominator cannot be 0 when counting down.
if(s . equals(" 1/x ")& amp； & code) {
t _ content = textfield . gettext()；
If(t _ content. equals(" 0 "){// Page 3
Textfield.setText ("Zero cannot be reciprocal");
Number = false;
} Otherwise {
textfield . settext(double . tostring( 1/double . parse double(t _ content)))；
}
}
//The user clicked the% button.
if(s . equals(" % " & amp； & code) {
if(data2==0){
t _ content = textfield . gettext()；
textfield . settext(t _ content)；
} Otherwise {
Boolean g = false;
for(int I = 0； I & lttextfield.getText (). Length (); i++)
If ('.'==textfield.getText (). charAt(i)){
G = true;
Break;
}
//If it is an even number, divide by 100.
if(g=true){
double dt EMP = double . parse double(textfield . gettext())；
dt EMP = dt EMP/ 100.0；
textfield . settext(double . tostring(dt EMP))；
}
//If it is an int number but divisible by 100, remove the last two zeros.
Otherwise {
if(integer . parse int(textfield . gettext())% 100 = = 0){
int itemp = integer . parse int(textfield . gettext())；
itemp/= 100；
textfield . settext(integer . tostring(itemp))；
}
//If it is an int number but cannot be divisible by 100, it will be treated as a Double number.
Otherwise {
double dt EMP = double . parse double(textfield . gettext())；
dt EMP = dt EMP/ 100.0；
textfield . settext(double . tostring(dt EMP))；
}
}
}//Page 4
}
//Handling of positive and negative numbers
if(s . equals("+/-"){
t _ content = textfield . gettext()；
if(t _ content . charat(0)= '-'){
textfield . settext(" ")；
String content;
for(int I = 1； I<t _ content.length (); i++){
textfield . settext(textfield . gettext()+t _ content . charat(I))；
}
} Otherwise {
textfield . settext("-"+t _ content)；
}
}
//The button pressed is the+button.
if(s . equals("+"){
Switch (pkey)
Case 0:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 1:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 2:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 3:
if(textfield.getText()。 Equal to ("0 "){
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
key =- 1；
data 2/= data 1；
textfield . settext(double . tostring(data 2))；
Break;
}
Default value:
data 2 = double . parse double(textfield . gettext())；
}
pkey = key = 0；
textfield . settext(" ")；
}
//Page 5
//The button pressed is the-button.
if(s . equals("-"){
Switch (pkey)
Case 0:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 1:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 2:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 3:
if(textfield.getText()。 Equal to ("0 "){
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
key =- 1；
data 2/= data 1；
textfield . settext(double . tostring(data 2))；
Break;
}
Default value:
data 2 = double . parse double(textfield . gettext())；
}
pkey = key = 1；
textfield . settext(" ")；
}
//The button pressed is the * button.
if(s . equals(" * "){
Switch (pkey)
Case 0:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 1:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 2:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 3:
If (textfield.gettext()。 Equals(" 0 "){// Page 6
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
key =- 1；
data 2/= data 1；
textfield . settext(double . tostring(data 2))；
Break;
}
Default value:
data 2 = double . parse double(textfield . gettext())；
}
pkey = key = 2；
textfield . settext(" ")；
}
//The button pressed is the/button.
if(s . equals("/"){
Switch (pkey)
Case 0:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 1:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 2:
data 2+= double . parse double(textfield . gettext())；
Break;
Case 3:
if(textfield.getText()。 Equal to ("0 "){
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
key =- 1；
data 2/= data 1；
textfield . settext(double . tostring(data 2))；
Break;
}
Default value:
data 2 = double . parse double(textfield . gettext())；
}
pkey = key = 3；
textfield . settext(" ")；
}//Page 7
//The pressed button is =, so find the result.
if(s . equals(" = " & amp； & code) {
//If the = button is not pressed for the first time,
if(pkey==5){
Switch (pkey)
Case 0:
data 2+= data 1；
textfield . settext(double . tostring(data 2))；
Break;
Case 1:
data 2-= data 1；
textfield . settext(double . tostring(data 2))；
Break;
Case 2:
data 2 * = data 1；
textfield . settext(double . tostring(data 2))；
Break;
Case 3:
if(textfield.getText()。 Equal to ("0 "){
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
data 2/= data 1；
textfield . settext(double . tostring(data 2))；
Break;
}
}
}
//If the = button is pressed for the first time,
Otherwise {
data 1 = double . parse double(textfield . gettext())；
Switch (key)
Case 0:
key =- 1；
data 2+= double . parse double(textfield . gettext())；
textfield . settext(double . tostring(data 2))；
Break;
Case 1:
key =- 1；
data 2-= double . parse double(textfield . gettext())；
textfield . settext(double . tostring(data 2))； //Page 8
Break;
Case 2:
key =- 1；
data 2 * = double . parse double(textfield . gettext())；
textfield . settext(double . tostring(data 2))；
Break;
Case 3:
if(textfield.getText()。 Equal to ("0 "){
Textfield.setText ("Delimiter cannot be zero");
Number = false;
} Otherwise {
key =- 1；
data 2/= double . parse double(textfield . gettext())；
textfield . settext(double . tostring(data 2))；
Break;
}
}
}
pkey = 5；
}
//Numeric button when the button is pressed
Otherwise {
Switch (s.charAt(0)){) (
Case "0":
Case "1":
Case "2":
Case "3":
Case "4":
Case "5":
Case "6":
Case "7":
Case "8":
Case "9":
Number = true;
textfield . settext(textfield . gettext()+s)；
Break;
//processing ...
Case ".":
t _ content = textfield . gettext()；
Boolean g = false; //Page 9
//Check the data in the computer column.
//If there is a decimal point, it will not be added when the user clicks the button.
for(int I = 0； I<t _ content.length (); i++){
if(t_content.charAt(i)== ' . '){
G = true;
Break;
}
}
//There is already a decimal point in the data.
If (g = = true)
Break;
//There is no decimal point in the data. The user clicks the decimal point and adds a decimal point.
If (g = = false)
textfield.setText(t_content+" . ");
}
}
}
Private string integer (string string) (
// TODO automatically generated method stub
Returns null
}
}