Import java.awt.event. *;
Import javax.swing. *;
Import javax.swing.border. *;
Import java.util.linkedlist; //Toolkit
Import java.text.numberformat; //Text package
/**
* java swing Simple Calculator
* @ The author is young
*
*/
The public class calculator extension framework implements the action listener//calculator class.
{
JTextField results;
number button number button[]；
operator button operator button[]；
Buttons radixpoint, positiveminus, backspace, reciprocal, equal, clear// Declarer variable.
//Count button, minus button, backspace button, countdown button, equal sign button and reset button.
Panel panel;
String operators [] = {"+","-","*", "/"};
LinkedList linked list;
boolean pressequal = false
Public Calculator ()//Construction
{
Super ("calculator");
linklist = new linked list()；
number button = new number button[ 10]；
for(int I = 0； I < = 9; i++) {
NumberButton[i] = new numeric button (i);
Numeric button [i]. addActionListener(this)；
}
operator button = new operator button[4]；
for(int I = 0； I<4; i++) {
operator button[I]= new operator button(operator[I])；
Operator button [i]. addActionListener(this)；
}
Radixpoint = new button (".");
Positiveminus = New button ("+/-");
back space = new Button(" CE ")；
Countdown = new button ("1/x");
Equal = New button ("=");
Clear = new button ("c");
radix point . set foreground(color . red)；
positive MINUS . set foreground(color . red)；
back space . set foreground(color . red)；
reciprocal . set foreground(color . red)；
equal . set foreground(color . red)；
clear . set foreground(color . red)；
radix point . addactionlistener(this)；
positive MINUS . addactionlistener(this)；
backspace . addactionlistener(this)；
reciprocal . addactionlistener(this)；
equal . addactionlistener(this)；
clear . addactionlistener(this)；
result = new JTextField( 10)；
result . sethorizontal alignment(JTextField。 Right);
result . set foreground(color . black)；
result . set background(color . white)；
Result.setFont (new font ("TimesRoman", font. Plain,14));
Result.setBorder (the new SoftBevelBorder(BevelBorder). Reduce));
result . set editable(false)；
Panel = new Panel()；
panel . set layout(new GridLayout(4，5))；
panel . add(number button[ 1])；
panel . add(number button[2])；
panel . add(number button[3])；
Panel.add (backspace);
panel . add(clear)；
panel . add(number button[4])；
panel . add(number button[5])；
panel . add(number button[6])；
panel . add(operator button[0])；
panel . add(operator button[2])；
panel . add(number button[7])；
panel . add(number button[8])；
panel . add(number button[9])；
panel . add(operator button[ 1])；
panel . add(operator button[3])；
panel . add(number button[0])；
panel . add(positive MINUS)；
Panel.add (reciprocal);
panel . add(radix point)；
Panel.add (equal to);
Add (result, "North");
Add (panel, "center");
addWindowListener(new window adapter(){
public void window closing(window event e){
system . exit(0)；
}
});
setSize(270，200)；
setLocation(300，230)；
set visible(true)；
}
Public void action performed (action event e)//Click the button to handle the event.
{
If (e.getsource () instance of number button)//number button
{
number button b =(number button)e . getsource()；
if (linklist.size() == 0) {
int number = b . get number()；
linklist . add("+number)；
result . settext("+number)；
pressequal = false
}
else if(linklist . size()= = 1 & amp； & amppressequal == false) {
int number = b . get number()；
String num =(String)linklist . get first()；
string s = num . concat("+number)；
linklist.set(0，s)；
result.setText
} else if(linklist . size()= = 1 & amp； & amppressequal == true) {
int number = b . get number()；
linklist . remove first()；
linklist . add("+number)；
pressequal = false
result . settext("+number)；
} else if (linklist.size() == 2) {
int number = b . get number()；
linklist . add("+number)；
result . settext("+number)；
} else if (linklist.size() == 3) {
int number = b . get number()；
String num =(String)linklist . get last()；
string s = num . concat("+number)；
linklist.set(2，s)；
result.setText
}
} else if (such as getsource () instance of operator button) //action button
{
operator button b =(operator button)e . get source()；
if (linklist.size() == 1) {
String Fu Hao = b.getoperator ();
Linklist.add (Fu Hao);
} else if (linklist.size() == 2) {
String Fu Hao = b.getoperator ();
Linklist.set( 1, Fu Hao);
} else if (linklist.size() == 3) {
String Fu Hao = b.getoperator ();
String number 1 =(String)linklist . get first()；
String number 2 =(String)linklist . get last()；
String operator =(String)linklist . get( 1)；
Try {
double n 1 = double . parse double(number 1)；
double N2 = double . parse double(number 2)；
double n = 0；
if(operator . equals("+"){
n = n 1+N2；
} else if(operator . equals("-"){
n = n 1-N2；
} else if(operator . equals(" * "){
n = n 1 * N2；
} else if(operator . equals("/"){
n = n 1/N2；
}
linklist . clear()；
linklist . add("+n)；
Linklist.add (Fu Hao);
result . settext("+n)；
} catch (abnormal ee) {
}
}
} else if (e.getsource () = = equal)//equal sign button
{
pressequal = true
if(linklist . size()= = 1 | | linklist . size()= = 2){
String num =(String)linklist . get first()；
result . settext("+num)；
} else if (linklist.size() == 3) {
String number 1 =(String)linklist . get first()；
String number 2 =(String)linklist . get last()；
String operator =(String)linklist . get( 1)；
Try {
double n 1 = double . parse double(number 1)；
double N2 = double . parse double(number 2)；
double n = 0；
if(operator . equals("+"){
n = n 1+N2；
} else if(operator . equals("-"){
n = n 1-N2；
} else if(operator . equals(" * "){
n = n 1 * N2；
} else if(operator . equals("/"){
n = n 1/N2；
}
result . settext("+n)；
linklist.set(0，" "+n)；
linklist . remove last()；
linklist . remove last()；
} catch (abnormal ee) {
}
}
} else if (e.getsource () = = radixpoint)//several buttons.
{
if (linklist.size() == 0) {
pressequal = false
} else if(linklist . size()= = 1){
string dot = radix point . get label()；
String num =(String)linklist . get first()；
String s = null
if(num . index of(dot)= =- 1){
S = num.concat (point);
linklist.set(0，s)；
} Otherwise {
s = num
}
linklist.set(0，s)；
result.setText
}
else if (linklist.size() == 3) {
string dot = radix point . get label()；
String num =(String)linklist . get last()；
String s = null
if(num . index of(dot)= =- 1){
S = num.concat (point);
linklist.set(2，s)；
} Otherwise {
s = num
}
result.setText
}
} else if (e.getsource () = = backspace)//backspace button
{
if (linklist.size() == 1) {
String num =(String)linklist . get first()；
if(num . length()& gt； = 1) {
num = num.substring(0，num . length()- 1)；
linklist.set(0，num)；
result . settext(num)；
} Otherwise {
linklist . remove last()；
result . settext(" 0 ")；
}
} else if (linklist.size() == 3) {
String num =(String)linklist . get last()；
if(num . length()& gt； = 1) {
num = num.substring(0，num . length()- 1)；
linklist.set(2，num)；
result . settext(num)；
} Otherwise {
linklist . remove last()；
result . settext(" 0 ")；
}
}
} else if (e.getsource () = = plus or minus)//minus button
{
if (linklist.size() == 1) {
String number 1 =(String)linklist . get first()；
Try {
double d = double . parse double(number 1)；
d =- 1 * d；
string str = string . value of(d)；
linklist.set(0，str)；
result . settext(str)；
} catch (abnormal ee) {
}
} else if (linklist.size() == 3) {
String number 2 =(String)linklist . get last()；
Try {
double d = double . parse double(number 2)；
d =- 1 * d；
string str = string . value of(d)；
linklist.set(2，str)；
result . settext(str)；
} catch (abnormal ee) {
}
}
} else if (e.getsource () = = countdown)//countdown button
{
if(linklist . size()= = 1 | | linklist . size()= = 2){
String number 1 =(String)linklist . get first()；
Try {
double d = double . parse double(number 1)；
d = 1.0/d；
string str = string . value of(d)；
linklist.set(0，str)；
result . settext(str)；
} catch (abnormal ee) {
}
} else if (linklist.size() == 3) {
String number 2 =(String)linklist . get last()；
Try {
double d = double . parse double(number 2)；
d = 1.0/d；
string str = string . value of(d)；
linklist.set(0，str)；
result . settext(str)；
} catch (abnormal ee) {
}
}
} else if (e.getsource () = = clear)//Clear button
{
pressequal = false
result . settext(" 0 ")；
linklist . clear()；
}
}
Public static void main (strinargs []) {
New calculator ();
}
}
Category Number Button Expand Button//Number Button Category
{
Int number;
Public numberbutton (int number)//construction
{
Super ("+number);
This.number = number;
set foreground(color . blue)；
}
public int getNumber() {
Quantity returned;
}
}
Class Operator Button Extension Button//Operator Symbol Button Class
{
String operator;
Common Operator Button (String Operator)//Construction
{
Super (operator);
this.operator = operator
set foreground(color . red)；
}
Public string getOperator() {
Return operator;
}
}