Assignment 6. Linked Lists

Due Friday, August 13 at 11:59 pm Pacific

  • Submissions received by the due date receive a small on-time bonus.
  • All students are granted a pre-approved extension or "grace period" of 24 hours after the due date. Late submissions are accepted during the grace period with no penalty.
  • The grace period expires Sat, Aug 14 at 11:59 pm Pacific, after which we cannot accept further late submissions.
  • In this course, we express all date/times in Pacific time GMT -7. Our Paperless submission system also displays/records due dates and submission times in Pacific time.

Last week, you gained experience working with pointers in the context of arrays and dynamic memory allocation. This week, you further strengthen your pointer skills by manipulating linked lists. The pointed-based linked structures are a fundamentally different way of representing sequences than the array-based approaches you worked with in the last assignment, and this assignment aims to build your familiarity with the joys, trials, and tribulations of working with linked lists. Along the way, you'll also deepen your understanding of real-world sorting algorithms, as well. By completing the following tasks, you will become a master of pointers and linked structures – to the point where you'll finally be able to proclaim with confidence, Thank U->Next!

Learning goals

  • Students will continue to build and improve their skills of working with pointers.
  • Students will be able to use their knowledge of pointers to traverse and investigate linked data structures in the debugger.
  • Students will understand the fundamental differences between storing data in contiguous memory location as compared to organizing data pointer links.
  • Students will gain practice with different "idioms" of linked list usage, including pointer rewiring and insertion/removal of nodes from linked lists.
  • Students will build an understanding of real-world sorting algorithms and the performance tradeoffs of sorting data represented in different underlying formats.

Assignment parts

This assignment consists of two short debugging/warmup exercises (warmup.cpp and labryinth.cpp) and a substantive programming task on linked lists (sorting.cpp).

  • Memory Debugging Warmup

    A collection of tools and strategies to prep you for working with linked lists.

  • Labyrinth

    A hybrid coding/debugging exercise where you’ll trace through pointers in the debugger to escape from a labyrinth.

  • Sorting Linked Lists

    A classic programming task: reordering the nodes of a linked list into sorted order.

Getting started

We provide a ZIP of the starter project. Download the zip, extract the files, and double-click the .pro file to open the project in Qt Creator.

📦 Starter code

The source files you will edit are labyrinth.cpp and sorting.cpp.

Additionally, you will answer questions in short_answer.txt.


Here are resources that will be helpful for this assignment:

Getting help

Working very closely with raw memory, pointers, and linked data structures is a challenging task! We always recommend drawing lots of diagrams and making use of the debugger whenever possible. As always, we're here to help you if you get stuck. You can reach out with a post on Ed, email your section leader, join in at office hours, or sign up for one-one-one help at the LaIR. For questions specific to your code, coming to LaIR is your best bet. If you cannot attend LaIR due to timezone issues, you may post your question on Ed. However, you must use a private post if you are including code so that you are not posting your solutions for the whole class to see.


Before you call it done, run through our submit checklist to be sure all your ts are crossed and is dotted. Then upload your completed files to Paperless for grading.

Please submit only the files you edited; for this assignment, these files will be

  • labyrinth.cpp
  • sorting.cpp
  • short_answer.txt

🏁 Submit to Paperless

Note: On Paperless, all due dates and submission times are expressed in Pacific time.