Palindrome String In Java

What is Palindrome?

A Palidrome string is a string where if we reverse the string, the word will be same.

A palindrome is a word, number, phrase, or other sequence of characters which reads the same backward as forward.

Example: madam, refer, redivider

The logic in Java for implementation is very simple.,

Reverse the string
Compare the reversed string with the input string,
- If it is same, then Palidrome String
- Else not a Palindrome String.

package my.test;
public class Palindrome {
	public static void main(String[] args) {
		String string1 = "abcdcba";
		String string2 = "abcde";
		String string3 = "madam";
		String string4 = "refer";
		String string5 = "hello";
		
		System.out.println("Is String 1 Palindrome : " + isPalindrome(string1));
		System.out.println("Is String 2 Palindrome : " + isPalindrome(string2));
		System.out.println("Is String 3 Palindrome : " + isPalindrome(string3));
		System.out.println("Is String 4 Palindrome : " + isPalindrome(string4));
		System.out.println("Is String 5 Palindrome : " + isPalindrome(string5));
	}
	public static boolean isPalindrome(String str) {
		String reverseString = "";
		if(str!=null && str.length()>0) {
			char[] charArray = str.toCharArray();
			for(int i=charArray.length-1;i&gt;=0;i--){
				reverseString = reverseString + charArray&#91;i];
			}
		}else {
			return false;
		}
		System.out.println("Input String: " + str + " , Reversed String: " +reverseString);
		if(str.equalsIgnoreCase(reverseString)) {
			return true;
		}
		else{
			return false;
		}
	}
}

package my.test;

public class Palindrome {

public static void main(String[] args) {

String string1 = "abcdcba";

String string2 = "abcde";

String string3 = "madam";

String string4 = "refer";

String string5 = "hello";

System.out.println("Is String 1 Palindrome : " + isPalindrome(string1));

System.out.println("Is String 2 Palindrome : " + isPalindrome(string2));

System.out.println("Is String 3 Palindrome : " + isPalindrome(string3));

System.out.println("Is String 4 Palindrome : " + isPalindrome(string4));

System.out.println("Is String 5 Palindrome : " + isPalindrome(string5));

}

public static boolean isPalindrome(String str) {

String reverseString = "";

if(str!=null && str.length()>0) {

char[] charArray = str.toCharArray();

for(int i=charArray.length-1;i>=0;i--){

reverseString = reverseString + charArray[i];

}

}else {

return false;

}

System.out.println("Input String: " + str + " , Reversed String: " +reverseString);

if(str.equalsIgnoreCase(reverseString)) {

return true;

}

else{

return false;

}

Output:

Input String: abcdcba , Reversed String: abcdcba
Is String 1 Palindrome : true
Input String: abcde , Reversed String: edcba
Is String 2 Palindrome : false
Input String: madam , Reversed String: madam
Is String 3 Palindrome : true
Input String: refer , Reversed String: refer
Is String 4 Palindrome : true
Input String: hello , Reversed String: olleh
Is String 5 Palindrome : false

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