Palindrome 1

PalindromeChecker.java

public class PalindromeChecker {
    public static void main(String[] args) {
        String[] sWordsToCheck = new String[] { 
        		"gatemannametag", //p
        		"abcdefghijklmnopqrtuvwxyz", // not p
        		"aaaaa1aaaaa", //p
        		"aaaaa12aaaaa", // not p
        };

        for(int i=0; i<sWordsToCheck.length; ++i) {
        	String sWordToCheck = sWordsToCheck[i];
        	
	        System.out.print("palindrome1: ");
	        if(isPalindrome1(sWordToCheck))
	            System.out.println(sWordToCheck + " Is a Palindrome ");
	        else
	            System.out.println(sWordToCheck + " Is Not a Palindrome ");
	
	        System.out.print("palindrome2: ");
	        if(isPalindrome2(sWordToCheck))
	            System.out.println(sWordToCheck + " Is a Palindrome ");
	        else
	            System.out.println(sWordToCheck + " Is Not a Palindrome ");
	
	        System.out.print("palindrome3: ");
	        if(isPalindrome2(sWordToCheck))
	            System.out.println(sWordToCheck + " Is a Palindrome ");
	        else
	            System.out.println(sWordToCheck + " Is Not a Palindrome ");
        }

    }


    public static boolean isPalindrome3(String sWordToCheck) {
        return sWordToCheck.equals(new StringBuffer(sWordToCheck).reverse().toString());
    }

    public static boolean isPalindrome1(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
    }


    public static boolean isPalindrome2(String sWord) {
    	int len = sWord.length();
        int halfLen = sWord.length()/2;
        for (int i = 0; i < halfLen; i++) {
            if (sWord.charAt(i) != sWord.charAt(len - i - 1)) {
                return false;
            }
        }

        return true;
    }
}