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Language/Type: Java recursion recursive programming
Author: Stuart Reges (on 2014/02/13)

Write a recursive method called isPalindrome that takes a string as a parameter and that returns true if the string is a palindrome and false if it is not. A palindrome is a string like "racecar" that has the same sequence of characters when written forwards and backwards. Notice that in a palindrome, the first and last characters match, as do the second and second-to-last, the third and third-to-last, and so on. The table below includes various method calls and the value returned:

        Method Call       Result      Method Call               Result
        isPalindrome("radar")     true        isPalindrome("123321")    true
        isPalindrome("hah")       true        isPalindrome("peer")      false
        isPalindrome("peep")      true        isPalindrome("ab")        false
        isPalindrome("x")         true        isPalindrome("a ba")      false
        isPalindrome("")          true        isPalindrome("ABba")      false

You are restricted to the following String methods:

    charAt(index)                  returns the character at the given index
    length()                       returns the length of the string
    substring(fromIndex, toIndex)  returns a new string that is a substring of this string from startIndex (inclusive) to stopIndex (exclusive)

For example, if a String s stores the text "hello", then:

    s.charAt(0) returns 'h'
    s.length() returns 5
    s.substring(1, 3) returns "el"

You are not allowed to construct any structured objects (no array, ArrayList, String, StringBuilder, etc) and you may not use a while loop, for loop, or do/while loop to solve this problem; you must use recursion.

Type your solution here:

This is a method problem. Write a Java method as described. Do not write a complete program or class; just the method(s) above.

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