Important Notice:

Practice-It will be discontinued as of November 1st, 2024. After this date, the website will remain online for a transitional period, but login will be restricted to University of Washington NetID authentication. This marks the next phase towards the platform's full retirement. Thank you for your use and support of the application over the years.

If you are looking for an alternative, a similar tool, CodeStepByStep, was developed independently by the original author of Practice-It, and is available at codestepbystep.com**

logo Practice-It logo

Main Page → Problems → Solve a Problem

BJP4 Exercise 14.2: stutter

Language/Type: Java Collections Stacks and Queues stutter
Author: Jeff Prouty (on 2016/09/08)

Write a method stutter that takes a stack of integers as a parameter and replaces every value in the stack with two occurrences of that value. For example, suppose the stack stores these values: 

bottom [3, 7, 1, 14, 9] top

Then the stack should store these values after the method terminates: 

bottom [3, 3, 7, 7, 1, 1, 14, 14, 9, 9] top

Notice that you must preserve the original order. In the original list the 9 was at the top and would have been popped first. In the new stack the two 9s would be the first values popped from the stack. You may use a single queue as auxiliary storage to solve this problem.

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.

You must log in before you can solve this problem.


Log In

If you do not understand how to solve a problem or why your solution doesn't work, please contact your TA or instructor.
If something seems wrong with the site (errors, slow performance, incorrect problems/tests, etc.), please

Is there a problem? Contact a site administrator.