Question

A class Flipgram has been defined to flip the letters of the left and right halves of a non-heterogram word. If the word has odd number of characters, then the middle letter remains at its own position.
A heterogram is a word where no letter appears more than once.

Example 1: INPUT : BETTER
                   OUTPUT: TERBET

Example 2: INPUT : NEVER
                   OUTPUT: ERVNE

Example 3: INPUT : THAN
                   OUTPUT: HETEROGRAM

The details of the members of the class are given belwo:

Class name:	Flipgram
Data member/instance variable:
word:	to store a word
Methods/member functions:
Flipgram(String s):	parameterised constructor to assign word = s
boolean ishetero( ):	to return true if word is a heterogram else return false
String flip ( ):	to interchange the left and right sides of a non-heterogram word and return the resultant word
void display ( ):	to print the flipped word for a non-heterogram word by invoking the method flip( ). An appropriate message should be printed for a heterogram word

Specify the class Flipgram giving the details of the constructor(String), boolean ishetero( ), String flip( ) and void display( ). Define a main( ) function to create an object and call the functions accordingly to enable the task.

Answer 1

public class Flipgram {
  private String word;
  // Parameterised constructor
  public Flipgram(String s) {
    word = s;
  }
  // Method to check if the word is a heterogram
  public boolean ishetero() {
    // Convert to lowercase to make case-insensitive
    comparison
    String lowerWord = word.toLowerCase();
    for (int i = 0; i < lowerWord.length(); i++) {
      char currentChar = lowerWord.charAt(i);
      // Check if the current character appears again
      in the remaining string
      if (lowerWord.indexOf(currentChar, i + 1) !=-1){
        return false;
      }
    }
    return true;
  // Method to flip the left and right halves of a non-
  heterogram word
  public String flip() {
    int length = word.length();
    int half = length/2;
    //1f length is even, simply swap the two halves
    if (length % 2 == 0) {
      String left = word substring(0, half);
      String right = word.substring(half);
      return right + left;
    }
    // If length is odd, swap halves keeping middle
    character in place
    else {
      String left = word.substring(0, half);
      String right = word substring (half + 1);
      char middle = word.charAt(half);
      return right + middle + left;
    }
  }
  // Method to display the result
  public void display() {
    if (ishetero()) {
      System.out.println("HETEROGRAM");
    } else {
      System.out.println(flip());
    }
  }
  // Main method to test the class
  public static void main(String[] args) {
    // Test cases from the examples
    Flipgram f1 = new Flip Gram("BETTER");
    f1.display(); // Should print "TERBET"
    Flipgram f2 = new Flip Gram("NEVER");
    f2.display(); // Should print "ERVINE"
    Flipgram f3 = new Flip Gram("THAN");
    f3.display(); // Should print "HETEROGRAM"
   }
}