Java implements a simple Calculator class instance _java

The examples in this article describe the Java implementation of a simple calculator class. Share to everyone for your reference. as follows:

Package chap;
Import Java.awt.BorderLayout;
Import Java.awt.Color;
Import Java.awt.FlowLayout;
Import Java.awt.GridLayout;
Import java.awt.event.ActionEvent;
Import Java.awt.event.ActionListener;
Import Java.text.DecimalFormat;
Import Javax.swing.JButton;
Import Javax.swing.JFrame;
Import Javax.swing.JPanel;
Import Javax.swing.JTextField;
  public class Calculator {private JFrame frame;
  Private JPanel Panel,panelkeys,panelkeys_up,panelkeys_down; Private JTextField textcomputer;//Computing area private JButton buttonbk,buttonc;//backspace and clear 0 keys private JButton button[];//Digital key Group PR Ivate JButton buttondot,buttonaddsub,buttonadd,buttonsub,buttonmul,buttondiv,button1,button2,button3,buttonequal
  ;
  Private double result;//calculation result private final short ADD = 1;
  Private final short SUB = 2;
  Private final short MUL = 3;
  Private final short DIV = 4;
    Private short operator = -1;//operator Public Calculator () {frame = new JFrame ("Computer");
    Frame.setsize (400, 250);
  panel = new JPanel ()//Global panel  Panel.setvisible (TRUE);
    Frame.setvisible (TRUE);
    Frame.getcontentpane (). Add (panel);
    ActionListener listener = new Computeractionlistener ();/key listener//calculation Area Textcomputer = new JTextField (15);
    Textcomputer.settext ("");
    Textcomputer.seteditable (FALSE);
    Textcomputer.setbackground (New Color (255,255,255));
    Function key upper Half panelkeys_up = new JPanel ();
    Panelkeys_up.setlayout (New FlowLayout (flowlayout.right));
    BUTTONBK = new JButton ("Backspace");
    Buttonbk.setforeground (New Color (255,0,0));
    Buttonc = new JButton ("C");
    Buttonc.setforeground (New Color (255,0,0));
    Buttonbk.addactionlistener (listener);
    Buttonc.addactionlistener (listener);
    Panelkeys_up.add (BUTTONBK);
    Panelkeys_up.add (Buttonc);
    Function key lower part Panelkeys_down = new JPanel ();
    Panelkeys_down.setlayout (new GridLayout (4,5));
    button = new JBUTTON[10];
      for (int i = 0;i < button.length;i++) {Button[i] = new JButton (integer.tostring (i)); button[i].seTforeground (New Color (255,0,0));
    } buttonaddsub = new JButton ("+ +");
    Buttonaddsub.setforeground (New Color (255,0,0));
    Buttonadd = new JButton ("+");
    Buttonadd.setforeground (New Color (255,0,0));
    Buttonsub = new JButton ("-");
    Buttonsub.setforeground (New Color (255,0,0));
    Buttonmul = new JButton ("*");
    Buttonmul.setforeground (New Color (255,0,0));
    Buttondiv = new JButton ("/");
    Buttondiv.setforeground (New Color (255,0,0));
    button1 = new JButton ();
    Button2 = new JButton ();
    Button3 = new JButton ();
    Button1.setforeground (New Color (255,0,0));
    Button2.setforeground (New Color (255,0,0));
    Button3.setforeground (New Color (255,0,0));
    buttonequal = new JButton ("=");
    Buttonequal.setforeground (New Color (255,0,0));
    Buttonaddsub.addactionlistener (listener);
    Buttonadd.addactionlistener (listener);
    Buttonsub.addactionlistener (listener);
    Buttonmul.addactionlistener (listener);
    Buttondiv.addactionlistener (listener); BUttonequal.addactionlistener (listener);
    for (int i = 0; I <=9 i++) {Button[i].addactionlistener (listener);
    for (int i = 0; I <=9 i++) {panelkeys_down.add (button[i]);
    } panelkeys_down.add (Buttonaddsub);
    Panelkeys_down.add (Buttonadd);
    Panelkeys_down.add (buttonsub);
    Panelkeys_down.add (Buttonmul);
    Panelkeys_down.add (BUTTONDIV);
    Panelkeys_down.add (buttonequal);
    Panel.setlayout (New BorderLayout ());
    Panel.add (Textcomputer,borderlayout.north);
    Panel.add (Panelkeys_up,borderlayout.center);
  Panel.add (Panelkeys_down,borderlayout.south); Class Computeractionlistener implements actionlistener{@Override public void actionperformed (ActionEvent even
      T) {//TODO auto-generated method stub Object Keybutton = Event.getsource ();
      String text = Textcomputer.gettext ();
      DecimalFormat df = new DecimalFormat ("0.###########"); Backspace if (Keybutton = = BUTTONBK && text.lengtH () > 0) {textcomputer.settext (text.substring (0,text.length ()-1));
        //c key if (Keybutton = = buttonc) {result = 0;
      Textcomputer.settext ("");
        }//numeric key for (int i=0;i<10;i++) {if (Keybutton = = Button[i]) {textcomputer.settext (text+i);
      } if (Keybutton = = Buttonadd) {operator = 1;
      } if (Keybutton = = buttonsub) {operator = 2;
      } if (Keybutton = = Buttonmul) {operator = 3;
      } if (Keybutton = = buttondiv) {operator = 4; }//Symbol key if (Keybutton = Buttonadd | | keybutton = = Buttonsub | | keybutton = BUTTONMUL | | keybutton = = Buttondi V | |
          Keybutton = = buttonequal) {switch (operator) {case Add:result + = double.parsedouble (text);
        Break
          Case Sub:result-=double.parsedouble (text);
        Break
          Case Mul:result *=double.parsedouble (text); BreAk
          Case Div:result/=double.parsedouble (text);
        Break
        Default:result = double.parsedouble (text);
      } textcomputer.settext ("");
      } if (Keybutton = = buttonequal) {Textcomputer.settext (string.valueof (result));
  }} public static void Main (String args[]) {new Calculator ();

 }
}

I hope this article will help you with your Java programming.