Upon completion of this lab, you should be able to understand recursive thinking in the solution of a simple problem.
Upon completion of this lab, you should be able to understand how recursive algorithms work. For prepation, review the lecture notes on recursion.
You should be able to answer the following questions correctly in order to be successful in Exercises 1 and 2.Consider the string defined by
String sample = "CS 1027b";What would be returned by each of the following method calls?
Download the file RecursionLab.java. Your task is to fill
in the code for a recursive method that prints a string backwards. For
example, for the parameter string "Java", your method would print
"avaJ". The header of this method is
public static void
reversePrint(String inString) Note that the method is static,
i.e. it is a class method, and will not be invoked on an object. (See
main method to see how it is invoked.)
if the parameter string is empty (the base case) return from the method else print the last character of the parameter string call reversePrint with the substring that does not include the last character as the parameterYou can simplify the algorithm, by instead using the test
if the string is not empty.You should be able to write the algorithm using just the
Now you will write a recursive method that returns the reverse of a string. For example, for the parameter string "Java"”, your method would return the string "avaJ". The header of your method should be
public static String reverseString(String inString)
Add this method to the file
if the parameter string is empty (the base case) return the null string as the result string else result string is the last character of the parameter string, concatenated with the reverse of the substring that does not include the last character return the result stringYou should be able to write the algorithm using just the
Add the following code to the main method in RecursionLab.java to test your reverseString method:
// test reverseString String revString = reverseString(inString); System.out.println(revString);
Write a program that asks the user to input a string and then
reverseString to determine whether or not
the string is a palindrome. A palindrome is a sequence of characters that reads the
same both forwards and backwards, for example mom, radar, racecar.
Finally, write a recursive method with the header
public static boolean isPalindrome(String s)
true if the parameter string is a palindrome and
false if it is not.