Question

You are to name your package assign1 and your file Palindrome.java.

Palindrome Class

Palindrome

- testString : String

+ Palindrome (String) + isPalindrome (): boolean

The method isPalindrome is to determine if a string is a palindrome. A palindrome, for this assignment, is defined as a word or phrase consisting of alphanumeric characters that reads the same frontwards and backwards while ignoring cases, punctuation and white space. If there are no alphanumeric characters, the string is considered a palindrome. The method should return true if it is a palindrome and false otherwise.

Notice – there is no main, no input and no output for this assignment. You are limited to the following Java library classes.

- String
- Character

Here are the restrictions on this method. Up to 20% penalty if not followed.

1. You may NOT return from the inside of a loop.
2. You may NOT break from the inside of a loop.
3. You may use ONLY ONE loop (either while or do-while).

4. You may NOT copy the String to another String.
5. You may NOT process the String more than one time (only make one pass

through it).
6. You must STOP processing as early as possible (when you find that it is or is not

a palindrome). In other words, using a for loop is not a good solution.

Answer 1

Program code in java:

//declaring package
package assign1;

//class definition
public class Palindrome {
    //variable declaration
    String testString;
    //constructor
    public Palindrome(String text) {
        //assigning value to the variable after removing all the spaces and putting text in lower case
        testString=text.replaceAll("\\s", "").toLowerCase();
    }
    //method to find if the string is palindrome or not
    boolean isPalindrome(){
        System.out.println("Provided text is: "+testString);
        //variable declaration
        boolean flag=true;
        //finding the length of string and storing in variable
        int len=testString.length();
        //running the loop to find if the string is pallindrome
        for(int i=0; i<=len/2;i++){
            //comparing each character in the string and if the are not equal, reset the flag
            if(testString.charAt(i)!=testString.charAt(len-i-1)){
                flag=false;
            }
        }
        //return true if the string is palindrome or false if it is not
        return flag;
    }
    //main method
    public static void main(String[] args) {
        //creating object and providing the string to the constructor
        Palindrome pr=new Palindrome("Hello tmolleh");
        //claling the function to find the palindrome and storing the result in varianble
        boolean val=pr.isPalindrome();
        //checking for the value of variable
        if(val==true){//true means the string is palindrome
            System.out.println("The given text is a palindrome");
        }
        else{//false if string is not palindrome
            System.out.println("The given text is not a palindrome");
        }    
    }
    //end of main method
}
//end of class

Output: