CSC 132 Fall 2000

Lab 4

Due: end of today's lab, 5 October 2000

15 points

"Palindrome"

You will need files CharList.java, PalApplet.java and PalApplet.html from the eccentric download folder for Lab 4. Note: to download the HTML file you need to right-click then "save target as..". The CharList class is identical to Lab 3's IntList class, except the item stored in a node is a character (char) instead of an integer (int). The source code is well documented with javadoc-style comments so you can read about it here. Like IntList, CharList uses a private inner class called Node, and CharList methods provide all node and list maintenance.

The purpose of the applet is to determine whether or not an input word is a palindrome. A palindrome is a word spelled the same either backward or forward. The word will be entered in an AWT text field and stored in a linked list with one character per node, starting with the head node. The applet will then determine whether it is a palindrome by making a copy of the list in reverse order then checking the original list against the copy for equality. If the original list and its reversed copy contain the same sequence of characters, it is a palindrome otherwise not.

Your assignment is to implement the two CharList methods required to support this applet: reverse() and equals(). The methods are outlined in CharList.java. You are to fill in the details. You must implement reverse to make only one traversal of the original list.

// No preconditions or postconditions.
// Returns a CharList object which is a copy of the original 
// ("this") object only with the nodes in reverse order. The
// original list is not modified. You must do this in one 
// traversal of the original list.
public CharList reverse()
{
	CharList copyRev = new CharList();
	// you implement. 
	return copyRev;
}
// No preconditions or postconditions.
// Returns true if theList stores same sequence of characters 
// as "this", false otherwise.
public boolean equals(CharList theList)
{
	return false; // you implement, and replace this.
}

• Use PalApplet.java to test your code. PalApplet.html will launch it. Use of the applet should be pretty self-explanatory. Note there is a "Debug" checkbox. If Debug is checked, debugging information will be output to the text area. You might find this feature useful for testing. In addition, I can use it to determine partial credit in case you get one method working but not the other.
• Submit the modified CharList.java file to your eccentric upload folder. Do not submit the driver applet.
• Do not make any changes to CharList.java except within the body of reverse() or equals(). For grading, I will copy them from your program into mine before compiling.
• You are not required to document your code, but please use self-documenting identifiers.
• The name of this assignment contains, as a substring, the last name of one member of a well-known comedy troupe. What is his full name and the name of the troupe? Put your answers into the comments area for reverse(). No bonus points, too easy.

[ Assignments | CSC 132 | Peter Sanderson | Computer Science | SMSU ]

Peter Sanderson ( PeteSanderson@smsu.edu )