import java.awt.*;
   import javax.swing.*;
   import java.awt.event.*;

    public class Calc_simpleInterest extends JFrame
   {
      private static final int WIDTH = 400;
      private static final int HEIGHT = 200;
    
      private JLabel principalamountL, investmenttimeL, interestrateL,simpleinterestL;
      private JTextField principalamountTF, investmenttimeTF, interestrateTF,simpleinterestTF;
      private JButton calculateB, resetB, exitB;
        
       private CalculateButtonHandler cbHandler;
      private ResetButtonHandler rbHandler;
      private ExitButtonHandler ebHandler;
        
         public Calc_simpleInterest()
      {
         principalamountL = new JLabel("Principal Amount: ", SwingConstants.LEFT);
         investmenttimeL = new JLabel("Investment Time(in years): ", SwingConstants.LEFT);
         interestrateL = new JLabel("Interest Rate(%): ", SwingConstants.LEFT);
         simpleinterestL = new JLabel("Simple interest",SwingConstants.LEFT);
            
         principalamountTF = new JTextField(10);
         investmenttimeTF = new JTextField(10);
         interestrateTF = new JTextField(10);
            simpleinterestTF = new JTextField(10);
        
        //SPecify handlers for each button and add (register) ActionListeners to each button.
         calculateB = new JButton("Calculate Interest");
         cbHandler = new CalculateButtonHandler();
         calculateB.addActionListener(cbHandler);
         resetB = new JButton("Reset(Clear)");
         rbHandler = new ResetButtonHandler();
         resetB.addActionListener(rbHandler);
         exitB = new JButton("Close Program");
         ebHandler = new ExitButtonHandler();
         exitB.addActionListener(ebHandler);
        
         setTitle("Calculation of Simple Interest");
         Container pane = getContentPane();
         pane.setLayout(new GridLayout(6,2));
        
        //Add things to the pane in the order you want them to appear (left to right, top to bottom)
         pane.add(principalamountL);
            pane.add(principalamountTF);
            
            pane.add(investmenttimeL);
         pane.add(investmenttimeTF);
                
         pane.add(interestrateL);
         pane.add(interestrateTF);
            
            pane.add(simpleinterestL);
            pane.add(simpleinterestTF);

         pane.add(calculateB);
         pane.add(resetB);
         pane.add(exitB);
        
         setSize(WIDTH, HEIGHT);
         setVisible(true);
         setDefaultCloseOperation(EXIT_ON_CLOSE);
      }
    
       private class CalculateButtonHandler implements ActionListener
      {
          public void actionPerformed(ActionEvent e)
         {
            double principalamount;
                double investmenttime;
                double interestrate;
                double simpleInterest;
            
            principalamount = Double.parseDouble(principalamountTF.getText()); //We use the getText & setText methods to manipulate the data entered into those fields.
            investmenttime = Double.parseDouble(investmenttimeTF.getText());
                interestrate = Double.parseDouble(interestrateTF.getText());
           simpleInterest = (principalamount * interestrate * investmenttime) / 100.0;

            
            simpleinterestTF.setText("" + simpleInterest);
         }
      }
  
       public class ResetButtonHandler implements ActionListener
      
      {
          public void actionPerformed(ActionEvent e)
        
         {
        
                     interestrateTF.setText("");
                     investmenttimeTF.setText("");
                     principalamountTF.setText("");
                     simpleinterestTF.setText("");
        
         }
      }
       public class ExitButtonHandler implements ActionListener
      {
          public void actionPerformed(ActionEvent e)
         {
          
            System.exit(0);
        
         }
      }
    
       public static void main(String[] args)
      {
         Calc_simpleInterest simpObj  = new Calc_simpleInterest();
      }
    
   }