Dear readers, today we create a program to check whether the given String is Palindrome or not. Following are the ways to do it.
1) Using Stack
2) Using Queue
3) Using for/while loop
1 Example : Palindrome check Using Queue in Java
import java.util.Queue; import java.util.Scanner; import java.util.LinkedList; class PalindromeTest { public static void main(String[] args) { System.out.print("Enter any string:"); Scanner in=new Scanner(System.in); String inputString = in.nextLine(); Queue queue = new LinkedList(); for (int i = inputString.length()-1; i >=0; i--) { queue.add(inputString.charAt(i)); } String reverseString = ""; while (!queue.isEmpty()) { reverseString = reverseString+queue.remove(); } if (inputString.equals(reverseString)) System.out.println("The input String is a palindrome."); else System.out.println("The input String is not a palindrome."); } }
Output 1:
Enter any string:xyzzyx xyzzyx The input String is a palindrome.
Output 2:
Enter any string:xyz The input String is not a palindrome.
2 Example : Palindrome check Using for loop/While loop and String function charAt in Java
import java.util.Scanner; class PalindromeTest { public static void main(String args[]) { String reverseString=""; Scanner scanner = new Scanner(System.in); System.out.println("Enter a string to check if it is a palindrome:"); String inputString = scanner.nextLine(); int length = inputString.length(); for ( int i = length - 1 ; i >= 0 ; i-- ) reverseString = reverseString + inputString.charAt(i); if (inputString.equals(reverseString)) System.out.println("Input string is a palindrome."); else System.out.println("Input string is not a palindrome."); } }
Output 1:
Enter a string to check if it is a palindrome: aabbaa Input string is a palindrome.
Output 2:
Enter a string to check if it is a palindrome: aaabbb Input string is not a palindrome.
If you wanna use While Loop in above program then replace the for loop with this code:
int i = length-1; while ( i >= 0){ reverseString = reverseString + inputString.charAt(i); i--; }
3 Example : Palindrome check Using Stack in Java
import java.util.Stack; import java.util.Scanner; class PalindromeTest { public static void main(String[] args) { System.out.print("Enter any string:"); Scanner in=new Scanner(System.in); String inputString = in.nextLine(); Stack stack = new Stack(); for (int i = 0; i < inputString.length(); i++) { stack.push(inputString.charAt(i)); } String reverseString = ""; while (!stack.isEmpty()) { reverseString = reverseString+stack.pop(); } if (inputString.equals(reverseString)) System.out.println("The input String is a palindrome."); else System.out.println("The input String is not a palindrome."); } }
Output 1:
Enter any string:abccba The input String is a palindrome.