Palindrome in Java GUI

Submitted by donbermoy on Wednesday, May 7, 2014 - 16:28.

We all know that palindrome is a word or phrase that reads the same backward as forward. Here in this tutorial, we will create a program that can determine if the word inputted is a palindrome or not. Now, let's start this tutorial! 1. Open JCreator or NetBeans and make a java program with a file name of palindrome.java. 2. Import javax.swing package. Hence we will use a GUI (Graphical User Interface) here like the inputting the word.

import javax.swing.*;

3. Before coding in the Main, create first a function named isPalindrome as Boolean that has variable word as string as parameter of it.

   public static boolean isPalindrome(String word) {
    int left  = 0;                 // index of leftmost unchecked char
    int right = word.length() -1;  // index of the rightmost
  
    while (left < right) {         // continue until they reach center
        if (word.charAt(left) != word.charAt(right)) {
            return false;          // if chars are different, finished
        }
        left++;                    // move left index toward the center
        right--;                   // move right index toward the center
    }
  
    return true;                   // if finished, all chars were same
}

4. Initialized your variable in your Main, variable Str as string and make it as an input.

String Str;      
Str = JOptionPane.showInputDialog(null, "Enter String:");

5. Lastly, display the output of the program whether the word is a palindrome or not.

JOptionPane.showMessageDialog(null,"The word " + Str + " is palindrome: " + isPalindrome(Str) );

Take note that isPalindrome(Str) syntax triggers to access the boolean function that will validate the inputted word of variable Str. Output: output

Here's the full code of this tutorial:

import javax.swing.*;
 
public class palindrome {
 
  
    public static void main(String[] args) {
    
        String Str;   
     
        Str = JOptionPane.showInputDialog(null, "Enter String:");
 
        JOptionPane.showMessageDialog(null,"The word " + Str + " is palindrome: " + isPalindrome(Str) );
    }
   public static boolean isPalindrome(String word) {
    int left  = 0;                
    int right = word.length() -1;  
  
    while (left < right) {        
        if (word.charAt(left) != word.charAt(right)) {
            return false;      
        }
        left++;                   
        right--;                 
    }
  
    return true;                 
}
}

Hope this helps! :) Best Regards, Engr. Lyndon R. Bermoy IT Instructor/System Developer/Android Developer/Freelance Programmer If you have some queries, feel free to contact the number or e-mail below. Mobile: 09488225971 Landline: 826-9296 E-mail:[email protected] Visit and like my page on Facebook at: https://www.facebook.com/BermzISware Add and Follow me on Facebook: https://www.facebook.com/donzzsky

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