## CS 1401 Assignment #6

Date Assigned: Monday, October 8, or Tuesday, October 9, 2007.

Due Date: Monday, October 15, or Tuesday, October 16, 2007, before the beginning of your lab section.

Objective: The main objective of this assignment is to learn to use GUI.

Programming assignment: design and implement a GUI program that asks a student for a positive integer and transforms it into the binary code.

The following algorithm can be used to convert a decimal positive integer n into the binary form (as a string): you divide n by 2, keep a remainder. Divide the result by 2, keep a remainder, etc. until we get 0. The remainders, when read bottom to top, form the desired binary number.

Example of a binary code: for n = 13, we have

```13 / 2 = 6 rem 1
6 / 2 = 3 rem 0
3 / 2 = 1 rem 1
1 / 2 = 0 rem 1
```
When we read the remainders from bottom to top, we get 1101, which is exactly the binary representation of 13 -- since 1 * 8 + 1 * 4 + 0 * 2 + 1 * 1 = 8 + 4 + 1 = 13.

Hint: make a loop in which a string is gradually increased. Originally, the result-so-far is the input integer (e.g., 13), the string-so-far is empty. Within the loop, you divide the result-so-far by 2, compute the remainder, and add the corresponding one-character string ("0" or "1") to the left of the string-so-far, etc.

```
Solution:

public class Assignment6{

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

public class Binary extends JFrame{
private static final int WIDTH = 400;
private static final int HEIGHT = 400;
private JLabel decimalL, binaryL;
private JTextField decimalTF, binaryTF;
private JButton computeB, exitB;

private ComputeButtonHandler cbHandler;
private ExitButtonHandler ebHandler;

public GPA(){
//describe title
setTitle("Conversion to binary");

//create labels
decimalL = new JLabel("Enter a decimal number: ", SwingConstants.RIGHT);
binaryL = new JLabel("Its binary form is: ", SwingConstants.RIGHT);

//create text fields
decimalTF = new JTextField(20);
binaryTF  = new JTextField(20);

//create compute button
computeB = new JButton("Compute");
cbHandler = new ComputeButtonHandler();

//create exit button
exitB = new JButton("Exit");
ebHandler = new ExitButtonHandler();

//create the window
Container window = getContentPane();

//set the layout
window.setLayout(new GridLayout(3,2));

//place components of GUI into the pane

//set the size of the window and display it
setSize(WIDTH, HEIGHT);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}

private class ComputeButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent e){
int resultSoFar;
int remainder;
String stringSoFar = "";
String frontSymbol;

resultSoFar = Int.parseInt(decimalTF.getText());

//translating to binary
while (resultSoFar > 0){
//dividing by 2 and computing the remainder
remainder = resultSoFar % 2;
resultSoFar /= 2;

//adding a character to the string
if (remainder == 0)
{frontSymbol = "0";}
else
{frontSymbol = "1";}
stringSoFar = frontSymbol + stringSoFar;
}

binaryTF.setText(stringSoFar);
}
}
private class ExitButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
public static void main(String [] args){
Binary myBinary = new Binary();
}
}

```
Homework assignment: on a separate sheet of paper, solve Ex. 8, 16, and 18 at the end of Chapter 6.

Deliverables: as instructed by your TA.