Getting started
Import CS201_Lab18.zip (File→Import…→General→Existing Projects into Workspace→Archive File). You should see a project called CS201_Lab18 in the Package Explorer.
Your Task
A phrase is a palindrome when the sequence of the letters in the phrase is the same both forwards an backwards, ignoring space and punctuation. Some examples:
Rise to vote, sir
Able was I ere I saw Elba
A man, a plan, a canal - Panama!
A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal - Panama?
A Danish custard? Drat such sin, Ada!
Your task is to write a program which uses a stack to determine whether or not a phrase is a palindrome. A starting point is provided in the CheckPalindrome class, whose main method reads lines of input from System.in. You should modify the loop so that after each line of input is read, it checks the line to see if it is a palindrome, and then prints either “Palindrome” or “Not a palindrome” to System.out.
Use two collections: a stack of Character values and a queue of Character values:
Stack<Character> stack = new Stack<Character>();
Queue<Character> queue = new LinkedList<Character>();Note that the Character type is essentially equivalent to char, but because it is a class, Character values can be stored in collections such as Stacks. The Java compiler will automatically convert between char and Character values.
You will need to think about how the stack and queue can help you determine whether or not the input is a palindrome.
Here is an example run (user input in bold):
A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal - Panama? Palindrome Rise to vote, sir Palindrome Boy howdy! Not a palindrome quit program exits
Requirements and hints
You will need to treat a String object as a sequence of characters. You can use the length and charAt methods to get the length of a string and the value of a single character of the string, respectively. For example, here is how to iterate over all of the characters in a String:
String line = ...
for (int i = 0; i < line.length(); i++) {
char c = line.charAt(i);
// Do something with c
}Your program should ignore all characters other than letters. You can find out whether or not a character is a letter using the Character.isLetter method:
char c = ...
if (Character.isLetter(c)) {
// c is a letter
}You should also ignore case. One way to do this is by converting all letters to lower-case:
c = Character.toLowerCase(c);Running the program
Run the CheckPalindrome class as a Java Application (right-click, Run As→Java Application).
Type in some phrases and make sure that the program can successfully distinguish palindromes from non-palindromes.
Submitting
When you are done, submit the lab to the Marmoset server using either of the methods below.
From Eclipse
If you have the Simple Marmoset Uploader Plugin installed, select the project (CS201_Lab18) in the package explorer and then press the blue up arrow button in the toolbar. Enter your Marmoset username and password when prompted.
From a web browser
Save the project (CS201_Lab18) to a zip file by right-clicking it and choosing
Export…→Archive File
Upload the saved zip file to the Marmoset server as lab18. The server URL is
