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What is Palindrome ?

A string is a palindrome if the position of each character is the same even if the string is reversed. For example, “NAMAN” is a palindrome because the position of each character is the same even if the string “NAMAN” is reversed. Here we can use the predefined library method or not, to identify a string as palindrome

Example – check if a given String is palindrome

public class PalindromeStringChecker {

  public static void main(String[] args) {
    String strValue = "NAMAN";
    StringBuffer newStrValue = new StringBuffer();
    for (int i = strValue.length() - 1; i >= 0; i--) {
      newStrValue = newStrValue.append(strValue.charAt(i));
    }
    if (strValue.equalsIgnoreCase(newStrValue.toString())) {
      System.out.println(strValue + " is a palindrome String");
    } else {
      System.out.println(strValue + " is not a palindrome String");
    }
  }
}

Output

NAMAN is a palindrome String

Example – check if a given String is palindrome using reverse method

public class PalindromeStringCheker {
  
  public static void main(String[] args) {
    String strValue = "NAMAN";
    String reverseString = new StringBuffer(strValue).reverse()+"";
    if (strValue.equals(reverseString)) {
      System.out.println(strValue + " is palindrome String");
    } else {
      System.out.println(strValue + " is not palindrome String");
    }
  }
  
}

Output

NAMAN is palindrome String

Example – Just another way

public class PalindromStringCheker {
  public static void main(String args[]) {
    String currentValue = "";
    String compareValue = "";
    currentValue = "545";
    int length = currentValue.length();
    for (int i = length - 1; i >= 0; i--)
      compareValue = compareValue + currentValue.charAt(i);
    if (currentValue.equals(compareValue)) {
      System.out.println(currentValue + " is a palindrome.");
    } else {
      System.out.println(currentValue + " is not a palindrome.");
    }
  }
}

Output

545 is a palindrome.

Example

In above program,
If: currentValue= "553"
Output: 553 is not a palindrome.

If: currentValue= “proedu”
Output: proedu is not a palindrome.