parkcharge.java

很有趣的java程序~: 停车场收费问题

// 程序: 停车场收费问题
// 范例文件: ParkCharge.java

// Java core packages
import java.awt.*;
import java.awt.event.*;

// Java extension packages
import javax.swing.*;

public class ParkCharge extends JApplet implements ActionListener
{
	final int SHORT = 3, LONG = 24;
	final float DPH = 0.5f, MIN_CHARGE = 2.0f, MAX_CHARGE = 10.0f;
	float charges;
	float totalCharge = 0;
	int parkTime;	
	
	JTextField timeField;
	JLabel timeLabel;
	String output = "parkTime\tcharges\n";
	JTextArea result;
	JButton Button;
	JScrollPane scroller;

	public void init()
	{
		Container container = getContentPane();
		container.setLayout( new FlowLayout() );
		
		timeLabel = 
			new JLabel( "enter an integer and press enter!" );
		container.add( timeLabel );
		
		timeField =	new JTextField( 10 );
		container.add( timeField );		
		
		result = new JTextArea( 15, 25 );
		container.add( result );
		
		
		scroller = new JScrollPane( result );
		container.add( scroller );
		
		button = new JButton( "Click here" );
		button.addActionListener( this );
		container.add( button );
		
	}// end method init
	
	public void actionPerformed( ActionEvent e )
	{
		/*parkTime = Integer.parseInt( timeField.getText() );
		
		if( parkTime > LONG )
			JOptionPane.showMessageDialog( null, 
				"Please enter an integer less than 24!", "ERROR",
					JOptionPane.ERROR_MESSAGE );
				
		else if( parkTime < 0 )
			JOptionPane.showMessageDialog( null, 
				"Please enter an positive integer!", "ERROR",
					JOptionPane.ERROR_MESSAGE );
					
		else if( parkTime >= 0 && parkTime <= LONG )
		{
			charges = calculateCharges( parkTime );
			totalCharge += charges;
			output += parkTime + "\t" + charges + "\n";
		}
		
		else */
		if( timeField.getText().equals( "end" ) )
		{
			timeField.setEditable( false );
				
		/*	output += "\n\n\ntotalCharge is " + totalCharge + "\n";	
				
			//display result
					
			result.setText( output );*/
		}
		result.setText( output );
		result.append( "\n\ntotalCharge is:\t" + totalCharge + "\n" );
			
	}//end method actionPerformed
	
	public float calculateCharges( int parkTime )
	{
		if( 0 < parkTime && parkTime <= SHORT)
			return MIN_CHARGE;
		else
			return Math.min( MAX_CHARGE, MIN_CHARGE + ( float )DPH * ( parkTime - SHORT ) );
		
	}// end method calculateCharges	
	
}// end class ParkCharge