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

public class Twoscomplement extends JApplet {

    JTextField inputField;
    JTextField input32Field;
    JLabel errorLabel;

    public void init() {
	Container container = getContentPane();
	int panelRowsSize = 3;
	container.setLayout( new GridLayout( panelRowsSize, 1 ) );

	JPanel [] panelRows = new JPanel[panelRowsSize];
	for (int i=0; i<panelRowsSize; i++) {
	    panelRows[i] = new JPanel();
	    panelRows[i].setLayout( new FlowLayout() );
	    container.add( panelRows[i] );
	}

	Font bigFont = new Font( "Monospaced", Font.BOLD, 16 );

	JLabel inputLabel = new JLabel( "int" );
	inputLabel.setFont( bigFont );
	panelRows[0].add( inputLabel );

	inputField = new JTextField( 11 );
	inputField.setFont( bigFont );
	panelRows[0].add( inputField );
	inputField.addActionListener( 
        	new ActionListener () {
		    public void actionPerformed( ActionEvent event ) {
			
			errorLabel.setText( "" );
			input32Field.setText( "" );
			int num=0;
			boolean goodNum = true;
			try {
			    num = Integer.parseInt( inputField.getText() );
			} catch (NumberFormatException e) {
			    errorLabel.setText( "gack! try again" );
			    goodNum = false;
			}
			if ( goodNum ) {
			    String result="";
			    for (int i=31; i>=0; i--)
				result += ((num>>i) & 1);

			    input32Field.setText( "" + result );
			    
			}
		    }
		}
		
		);

	errorLabel = new JLabel( "" ) ;
	errorLabel.setFont( bigFont );
	panelRows[2].add( errorLabel );


	JLabel input32Label = new JLabel( "32 bits" );
	input32Label.setFont( bigFont );
	panelRows[1].add( input32Label );

	input32Field = new JTextField( 32 );
	input32Field.setFont( bigFont );
	panelRows[1].add( input32Field );
	input32Field.addActionListener( 
        	new ActionListener () {
		    public void actionPerformed( ActionEvent event ) {
			
			errorLabel.setText( "" );

			String input= input32Field.getText();
			if ( input.length() != 32 ) {
			    errorLabel.setText( "Must be 32 bits" );
			    inputField.setText( "" );
			}
			else {
			    char c;
			    int num = 0;
			    for (int i=31; i>=0; i--) {
				c = input.charAt( 31-i );
				if ( c!='0' && c!='1') {
				    errorLabel.setText( "Must be 32 bits" );
				    inputField.setText( "" );
				    return;
				}
				int j = c=='0' ? 0 : 1;
				num = (j<<i) | num;
			    }
			    inputField.setText( "" + num );
			}
		    }
		}
		);

    }


    public void start() {
	inputField.requestFocusInWindow();
    }


}