Ace the AP Computer Science Exam for High Schoolers/

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Solution Review: Is String a Palindrome?

Solution Review: Is String a Palindrome?

Have a look at the solution to the 'Is String a Palindrome?' challenge.

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Rubric criteria

Solution

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class Palindrome 
{
    public static void main(String args[]) 
    {
        System.out.println( checkPalindrome("madam"));
    }
    public static boolean checkPalindrome(String str)
    {
        if (str.length() == 0)
        {
            return true;
        }
        else
        {
            String reversedString = "";
            String currLetter;
            for(int i=0; i < str.length(); i++) 
            {
                currLetter = str.substring(i,i+1);
                // add the letter at index i to what's already reversed.
                reversedString = currLetter + reversedString;
            }
            if(str.equals(reversedString))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}

Rubric-wise explanation

Point 1:

Look at the header of the checkPalindrome() method at line 8. It’s a static function, and we call it without any need for an object. It takes the String parameter: str. First, we’ll handle the case of an empty string. If str is an empty string, we simply have to return true (see line 10). However, if str isn’t empty, we need to do the ...