V22.0101 ......Homework Assignment 1 Draft #2 ...... Fall 2007
Binary Representation of Numbers
Assigned: WED, Sept 19.
First and final version Due (by email to etutor):
(Marateck) MON, OCT 1, 11:59pm
Rewrite your first draft so that a class called
Binary stores the decimal number in the instance variable
numVal and the binary string corresponding to numVal will be
stored in the instance variable binStr. The value of the decimal number
is passed by the driver class Hw1 to the constructor.
The driver will have the following statements in an if block in the
Binary bin = new Binary(num);
boolean valid= bin.checkBin();
Note that getBin() and checkBin() have no
parameters. The necessary information is passed through the constructor.
The constructor has the heading
public Binary(int num) and will assign num to numVal. .
The class Binary will have the same two methods you have already written for
draft #1. They now have the following form:
You can "hard-wire" the example numbers into the main method, or you can read
them from the the keyboard using the JOptionPane class described in the text
book (page 45). the simplest form to use for assigning input to a string,
let's say number is String number =
JOptionPane.showInputDialog("Type your decimal number");. If you use this
approach, and are using Java 1.5 or lower remember to end the main
method with System.exit(0) otherwise the program will hang.
- public void getBin(). This produces the string consisting of the
binary equivalent of numVal prints it and assigns it to the instance
- public boolean checkBin()). This take the binary string in
binStr and checks to see if it correctly represents the number in
numVal. If it does, it returns true to the driver class, Hw1, else it
The main method in Hw1should
check to make sure the decimal value is between 0 and 255. If it is not, it
should print an informative error message (using System.out.println) and store
the number 0 instead.