Event Handling Program in Java Using Frame

/*Design a Frame to calculate Electricity Bill for Consumers, where Current Month Reading(CMR) unit consumed has been provided with Last Month Reading(LMR) unit consumed.
So, calculate net unit consumed and Net Bill.
User Inputs : Consumer Number , Consumer Name, Address ,Current Month Reading(CMR) , Last Month Reading(LMR), Consumer Code .
What to find :-----
->Net Unit Consumed :(NUC)
->Rate per unit(RPU):
if Type Of Connections (TOC) :
Type Of Connections are as follows : - ******************************************************
# Agriculture - A
# Domestic - D
# Commercial - C
# Industrial - I
# Invalid - Default
_____________________________________________________________________________________________________*/
import java.awt.*;
import java.awt.event.*;

public class ElectricityBill extends Frame implements ActionListener
{
Label LblConsNo,LblConsName,LblConsAddress;
Label LblLMR,LblCMR,LblConsCode,LblConsNUC,LblRPU,LblNetBill,LblTOC;
TextField txtConsNo,txtConsName,txtConsAddress;
private TextField txtLMR, txtCMR,txtConsCode,txtConsNUC,txtRPU,txtNetBill,txtTOC;
Button BtnCalculate,BtnCancel;
public ElectricityBill()
{
super("-:Electricity Bill Calculation:-");
setLayout(new FlowLayout());
LblConsNo = new Label(" Enter Consumer Number: ");
LblConsName = new Label(" Enter Consumer Name: ");
LblConsAddress = new Label(" Enter Consumer Address: ");
LblLMR = new Label(" Enter Last Month Reading:");
LblCMR = new Label(" Enter Current Month Reading:");
LblConsCode = new Label(" Enter Consumer Code:[ A / D / C / I ]");
LblConsNUC = new Label(" Net Unit Consumed:");
LblRPU = new Label(" Rate Per Unit:");
LblNetBill = new Label(" Net Bill:");
LblTOC = new Label(" Type Of Connection:" );
txtConsNo = new TextField(20);
txtConsName = new TextField(20);
txtConsAddress = new TextField(20);
txtLMR = new TextField(20);
txtCMR = new TextField(20);
txtConsCode = new TextField(20);
txtConsNUC = new TextField(20);
txtRPU = new TextField(20);
txtNetBill = new TextField(20);
txtTOC = new TextField(20);
BtnCalculate = new Button("Calculate");
BtnCancel = new Button("Cancel");
add(LblConsNo);
add(txtConsNo);
add(LblConsName);
add(txtConsName);
add(LblConsAddress);
add(txtConsAddress);
add(LblLMR);
add(txtLMR);
add(LblCMR);
add(txtCMR);
add(LblConsCode);
add(txtConsCode);
add(LblConsNUC);
add(txtConsNUC);
add(LblRPU);
add(txtRPU);
add(LblNetBill);
add(txtNetBill);
add(LblTOC);
add(txtTOC);
add(BtnCalculate);
add(BtnCancel);
BtnCalculate.addActionListener(this);/*Registration of the Calculate Button with the event Listener Interface */
BtnCancel.addActionListener(this);
//addWindowListener(this);
setSize(400,500);
setVisible(true);
}
public static void main(String args[]) { ElectricityBill eb = new ElectricityBill(); }

public void actionPerformed(ActionEvent e)
{
int ConsNo;
String ConsName;
String ConsAddress;
int LMR,CMR;
char Code;
float RPU,NUC,NetBill;
String TOC;
if(e.getSource()==BtnCancel) { System.exit(0);
}
if(e.getSource()==BtnCalculate) { ConsNo = Integer.parseInt(txtConsNo.getText());
ConsName = txtConsName.getText();
ConsAddress = txtConsAddress.getText();
LMR = Integer.parseInt(txtLMR.getText());
CMR = Integer.parseInt(txtCMR.getText());
Code = txtConsCode.getText().charAt(0);
switch(Code) { case 'A':
RPU = 1.75f;
txtRPU.setText(String.valueOf(RPU));
NUC = CMR - LMR;
txtConsNUC.setText(String.valueOf(NUC));
NetBill = RPU*NUC;
txtNetBill.setText(String.valueOf(NetBill));
txtTOC.setText("Agriculture");
break; case 'D':
RPU = 3.75f;
txtRPU.setText(String.valueOf(RPU));
NUC = CMR - LMR;
txtConsNUC.setText(String.valueOf(NUC));
NetBill = RPU * NUC;
txtNetBill.setText(String.valueOf(NetBill));
txtTOC.setText("Domestic");
break;
case 'C': RPU = 5.90f;
txtRPU.setText(String.valueOf(RPU));
NUC = CMR - LMR;
txtConsNUC.setText(String.valueOf(NUC));
NetBill = RPU*NUC;
txtNetBill.setText(String.valueOf(NetBill));
txtTOC.setText("Commercial");
break; case 'I':
RPU = 10.75f;
txtRPU.setText(String.valueOf(RPU));
NUC = CMR - LMR;
txtConsNUC.setText(String.valueOf(NUC));
NetBill = RPU*NUC;
txtNetBill.setText(String.valueOf(NetBill));
txtTOC.setText("Inductrial");
break;
default:
RPU=0;
txtRPU.setText(String.valueOf(RPU));
NUC = CMR - LMR;
txtConsNUC.setText(String.valueOf(NUC));
NetBill= RPU * NUC;
txtNetBill.setText(String.valueOf(NetBill));
txtTOC.setText("Invalid Type Connection");
}
}
}
/*public void windowClosing(WindowEvent we) {
System.exit(0); }
public void windowActivated(WindowEvent we) {
}
public void windowClosed(WindowEvent we)
{
}
public void windowDeactivated(WindowEvent we)
{
}
public void windowDeiconified(WindowEvent we)
{
}
public void windowIconified(WindowEvent we)
{ }
public void windowOpened(WindowEvent we)
{ }*/

}