My first small program.
Importjava.awt.*;Importjava.awt.event.*;Importjavax.swing.*;/*** A Simple Calculator program. * *@authorGuure *@version1.00 5/9/2015*/ Public classCalculatorextendsJFrameImplementsActionListener {/*** This class help close the Window. * */ Private classWindowcloserextendsWindowadapter { Public voidwindowclosing (WindowEvent We) {System.exit (0); }} JTextField Display=NewJTextField ("0"); JButton Reset=NewJButton ("CE"); Private Finalstring[] str = {"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", ".", "0", "=", "+"}; Jbutton[] Buttons=NewJbutton[str.length]; PublicCalculator () {Super("Calculator"); JPanel Panel1=NewJPanel (NewBorderLayout ()); Panel1.add ("Center", display); Panel1.add ("East", reset); JPanel Panel2=NewJPanel (NewGridLayout (4, 4)); inti; for(i = 0; i < str.length; i++) {Buttons[i]=NewJButton (Str[i]); Panel2.add (Buttons[i]); } getcontentpane (). setlayout (NewBorderLayout ()); Getcontentpane (). Add ("North", Panel1); Getcontentpane (). Add ("Center", Panel2); for(i = 0; i < str.length; i++) {Buttons[i].addactionlistener ( This); } reset.addactionlistener ( This); Display.addactionlistener ( This); Addwindowlistener (NewWindowcloser ()); SetSize (800, 800); SetLocation (400, 200); SetVisible (true); Pack (); } Public voidactionperformed (ActionEvent e) {Object target=E.getsource (); String label=E.getactioncommand (); if(target = =reset) {Handlereset (); } Else if("0123456789."). IndexOf (label) > 0) {handlenumber (label); } Else{handleoperator (label); } } BooleanIsfirstdigit =true; DoubleNumber = 0.0; String operator= "="; Public voidHandlenumber (String key) {if(isfirstdigit) {display.settext (key); Isfirstdigit=false; } Else if((Key.equals (")") && (Display.gettext (). IndexOf (".") < 0) {Display.settext (Display.gettext () )+ "."); } Else if(!key.equals (".") {Display.settext (Display.gettext () )+key); } } Public voidHandlereset () {Display.settext ("0"); Isfirstdigit=true; Operator= "="; } Public voidhandleoperator (String key) {if(Operator.equals ("+") ) { number+=double.valueof (Display.gettext ()); } Else if(Operator.equals ("-") ) { number-=double.valueof (Display.gettext ()); } Else if(Operator.equals ("*") ) { number*=double.valueof (Display.gettext ()); } Else if(Operator.equals ("/") ) { number/=double.valueof (Display.gettext ()); } Else if(Operator.equals ("=") ) { number=double.valueof (Display.gettext ()); } display.settext (string.valueof (number)); Operator=key; Isfirstdigit=true; } Public Static voidMain (string[] args) {NewCalculator (); }}
A simple calculator