The following method recognizes whether a String parameter consists of a specific pattern and returns True if the String has that pattern, false otherwise. Use this recursive method to answer the questions below.
public boolean patternRecognizer(String a)
{
if (a == null) return false;
else if (a.length( ) = = 1 | | (a.length( ) = = 2 && a.charAt(0) = = a.charAt(1) ) ) return True;
else if (a.length( ) = = 2 && a.charAt(0) != a.charAt(1) ) return false;
else if (a.charAt(0) == a.charAt(a.length( ) - 1))
return patternRecognizer(a.substring(1, a.length( ) - 1));
else return false;
}
-Which String below would result in patternRecognizer returning True?
A) "abcba"
B) "aaabbb"
C) "abcde"
D) "aabba"
E) all of the above Strings will result in the method returning True

Question

Quizplus · Accepted Answer

A) The method patternRecognizer returns True if the String is a palindrome. This can be seen by analyzing the code. If the String has 1 character, or 2 characters which are equal, it returns True, otherwise if the first and last characters are the same, it recursively calls itself with the substring starting at character 1 and going to the second to last character (so, since in "abcba" the first and last characters are the same, the method is called recursively with the substring "bcb"). Only if the first and last characters do not match is false returned. The only palindrome in the list of options is a, "abcba".

The Following Method Recognizes Whether a String Parameter Consists of a Specific