CODE FOR THE SIMPLE CALCULATOR IN JAVA A SAMPLE APPLICATION FOR SOFTWARE DEVOLVEMENT IN JAVA

//For any queries u can reach me at      d_ramu2002@yahoo.com

import java.awt.*;               

import java.awt.event.*;

// class-1 my own adapter 
class w extends WindowAdapter

{public void windowClosing(WindowEvent we){

System.exit(0);

}}
//CLASS-2 LOGIN CLASS 

       class login extends Frame implements ActionListener

              {

                     Label un,pwd;

              TextField tfun,tfpwd;

              Button ok,cancel;

login()

{

setLayout(null);

addWindowListener(new w());

un=new Label("username",Label.LEFT);

pwd=new Label("password",Label.LEFT);

un.setBounds(400,100,120,20);

pwd.setBounds(400,120,120,20);

add(un);

add(pwd);

tfun=new TextField();

tfpwd=new TextField();

tfun.setBounds(600,100,100,20);

tfpwd.setBounds(600,120,100,20);

add(tfun);

add(tfpwd);

ok=new Button("ok");

cancel=new Button("cancel");

ok.setBounds(400,180,40,20);

cancel.setBounds(600,180,40,20);

add(ok);

ok.addActionListener(this);

add(cancel);

ok.addActionListener(this);

cancel.addActionListener(this);

setBackground(Color.green);

setForeground(Color.red);

              }

       public void paint(Graphics g)

{

g.drawString("THIS THE LOGIN PAGE",400,60);

}

public void actionPerformed(ActionEvent ae)

{

String s=ae.getActionCommand();

                if(s.equals("ok"))

                {

                String s1=tfun.getText();

                String s2=tfpwd.getText();

                      System.out.println("   "+s1+" \n  "+s2); 

                        if((s1.equals("ramu"))&&(s2.equals("dayina")))

                                      {  

                                    compute c=new compute();

                                    c.setBounds(0,0,640,400);

                                    c.setVisible(true);

                                    c.setTitle("CALCULATOR");

                                    c.setBackground(Color.yellow);

                                    c.setForeground(Color.pink);

                                    dispose();

                                        }

                                        }

else if(s.equals("cancel"))

System.exit(0);

}

}

//CLASS-3 computational code

class compute extends Frame implements ActionListener

{

Label n1,n2,op,opr;

TextField tfn1,tfn2,tfop;

Choice copr;

Button submit,cancel,exit;

        compute()

        {

        setLayout(null);

        addWindowListener(new w());

        n1=new Label("number1",Label.LEFT);

        n2=new Label("number1",Label.LEFT);

        op=new Label("output",Label.LEFT);

        opr=new Label("operation",Label.LEFT);

        n1.setBounds(100,200,60,10);

        n2.setBounds(100,220,60,10);

        op.setBounds(400,200,60,10);

        opr.setBounds(300,400,80,10);

        add(n1);

        add(n2);

        add(op);

        add(opr);

             tfn1=new TextField();

             tfn2=new TextField();

             tfop=new TextField();

               tfn1.setBounds(160,200,40,20);

               tfn2.setBounds(160,220,40,20);

               tfop.setBounds(380,200,100,20);

                 add(tfn1);

                 add(tfn2);

                 add(tfop);

         copr=new Choice();

         copr.addItem("add");

         copr.addItem("sub");

         copr.addItem("mul");

         copr.addItem("div");

          copr.setBounds(380,400,60,20);

          add(copr);

      submit=new Button("submit");

      cancel=new Button("cancel");

      exit=new Button("exit");

                    submit.setBounds(400,300,50,20);

                    cancel.setBounds(500,300,50,20);

                    exit.setBounds(600,300,50,20);

                        add(submit);

                        add(cancel);

                        add(exit);

       submit.addActionListener(this);

        cancel.addActionListener(this);

        exit.addActionListener(this);

        }

        public void actionPerformed(ActionEvent ae)

     {

              String s=ae.getActionCommand();

                if(s.equals("submit"))

                           {

                           int n1=Integer.parseInt(tfn1.getText());

                           int n2=Integer.parseInt(tfn2.getText());

                               int res=0;

                            String si=copr.getSelectedItem();

                            if(si.equals("add"))

                                    res=(n1+n2);

                             else

                            if(si.equals("sub"))

                                res=(n1-n2);

                            else

                            if(si.equals("mul"))

                                res=(n1*n2);

                            else

                            if(si.equals("div"))

                                res=(int)n1/n2;

                            tfop.setText(""+res);}

                      else

                            if(s.equals("cancel"))

                            {

                                 tfn1.setText("");

                                 tfn2.setText("");

                                 tfop.setText("");

                             }

                             else

                             if(s.equals("exit"))

                                     System.exit(0);

                                  else

                                  System.out.println("");

                                                 }}

//class-4 main controller

class cal extends Frame

{

public static void main(String s[])

{

login l=new login();

l.setVisible(true);

l.setBounds(400,220,40,20);

l.setTitle("This is the Login page ");

}}

Class-1 my own adapter class (for adding window methods to my application i.e. exit minimize and so on)

Class-2 login class (user interface implementation PL)

Class-3 computational code (B.L)

Class-4 main class which assembles the above all classes

* the above code explains u how to create multiple frames in your project and as well as calling one frame from another (i.e communication between frames , data passing from one frame to another
OUTPUT:-

E:\>javac cal.java

E:\>java cal

   ramu

  dayina

  

 NOTE:- in the above code while adding the components to the frame study the locations to be appeared on the frame then set bound to the each components