Written by Julie Zelenski, with modifications by Nick Troccoli
For the exams, answering the questions is typically going to require good comprehension of the foundational concepts and the ability to analyze and apply them in a given situation. We are evaluating that not only did you successfully complete the assignments and labs, but that you came away with a comprehension you can demonstrate. We generally do not ask details that can/should be looked up on demand ("How do you printf a number in hexadecimal number padded to 8 digits?"). Many questions will ask you to write short passages of C code. Other questions may ask you to analyze C code: to trace its behavior, to compare or contrast two versions, identify and fix flaws, or describe a memory layout. Others may ask you short questions about material or code. There may also be short-answer thought questions that ask you to reason about system behavior, coding tasks, numeric representation and limitations, performance tradeoffs, and the like.
Before the exam
The long view. The mastery we are looking to assess with the exams isn't created by a night of cramming, it is built up throughout the quarter. Make it a priority to monitor your own progress and use our post-task self-checks listed at the end of each lab/assignment to identify holes or confusion to be shored up before moving on. In the ideal situation, you have established solid understanding of the material and the only exam preparation needed is practice applying your skills under exam-like conditions.
Make your notes sheet as part of exam prep. Reviewing topics and determining what information is worth including on your reference page(s) will remind you of where we've been and help you take stock of your comfort level with the course topics. Use this opportunity to identify any areas on which you feel weak and resolve dangling issues before heading into the exam.
Practice in simulated conditions. A good way to study for the programming problems is to take a problem (from lecture, lab, textbook) and write out your solution under test-like conditions. This is much more valuable than a passive review of the problem and its solution, when it becomes too easy to conclude “ah yes, I would have done that,” only to find yourself adrift during the real exam when there is no provided solution to guide you!
Get your questions answered. If there is a concept you’re a bit fuzzy on or you’d like to check your answer to a chapter exercise, or you wonder why a solution is written a particular way, get those questions answered before the exam. Swing by Helper Hours or post on the discussion forum; we’re happy to help!
During the exam
Scan all the problems first. Quickly peruse all questions before starting on any one. This allows you to “multitask”—as you are writing the more mundane parts of one answer, your mind can be brainstorming strategies or ideas for another problem in the background. You can also sketch out how to allocate your time between questions in the first pass.
Spend your time wisely. Don't get stuck on any particular problem. You'll earn more points from reasonable efforts across all problems than by perfecting one answer at the cost of leaving others blank. Take into account the point value assigned to each question when budgeting your time. Be conscious of which details are worth slowing down to get it right (e.g. allocating memory, getting the right typecast, correct pointer math, and so on) and which tasks can do with just a quick first draft (e.g. an off-by-one loop index or forgetting to initialize a counter).
Ask a question rather than answer the wrong one. If you are uncertain about what a question is asking or find some part of the question ambiguous, it's worth your time to ask the course staff for a clarification so you can be sure you are solving the right problem before you start working on it.
Pay attention to specific instructions. A problem statement may include detailed constraints and hints such as "use only bitwise operators" or "ignore the case when the string is empty" or "must run in constant time". You may want to highlight these instructions to be sure you don't overlook them. These constraints are not intended to make things difficult; typically we are trying to guide you in the direction of a straightforward and simple solution.
Save a little time for checking your work. Before submitting, reserve a few minutes to go back over your work. Check for matching parameter names passed into functions, etc. We try not to deduct points for minor things if it is obvious what you meant, but sometimes it is difficult to decipher your true intention. You might save yourself a few lost points by tidying up the details at the end.
The kind of systems coding we do in CS107 leaves much room for error, spanning the gamut from oversights such as forgetting to return the function result to more serious omissions such as failing to allocate memory for a pointer. Nearly everyone loses a few points that could have been avoided with more time and a chance to execute/test the code. However, a solid first-pass approximation that shows the correct conceptual understanding of the key issues will earn the bulk of the points and, in our analysis, deserves to be strongly distinguished from code that exhibits significant conceptual issues and would require much trial-and-error with compiler/debugger/Valgrind to turn into working code.
More broadly, the ability to analyze and reason about code in isolation is a valuable skill for any computer scientist. It forces you to think before you code, rather than leaning too much on the tools. At every step, you want to ensure that you understand the code you are writing, what it does, and how it works
After the exam
For most students, the assignment and exam performance are fairly well correlated but sometimes they do diverge a bit. It's pretty rare to rock the exam if your assignments didn't go well, but there are students who go into the exam with solid assignment scores and yet emerge with a disappointing outcome. What might explain this and what can you do about it?
Make sure you are mastering the material while completing the assignments. You should not complete assignments using trial or error techniques, make a change if you don't understand its implications, or only make modifications that the course staff tells you to. Even though you may get through the assignments, you won't be able to reproduce these results in an exam setting. The goal of an assignment is not to get the program to work, one way or another, it is about developing an understanding of how and why it works, and being able to take that understanding and write similar code in any environment, including one that doesn't have the luxury of a compiler/debugger/Valgrind/CA/sanitycheck to tell your whether the code is correct or not.
Gauge your comfort with the material. Did you feel like you spent a lot of time looking through your materials and clarifying concepts during the exam? Did you feel that the mistakes you made on the exam were just small oversights, or more conceptual? Use the exam results to answer these questions about your understanding of the material and use them to prepare even better for next time.
Ensure comfort in the testing environment. If you feel that one of the reasons behind how you did on the exam was lack of comfort in the testing environment (no tools, time limits, etc.), make sure to practice more in test-like conditions. Review your exam, introspect on what happened, brainstorm tactics for next time, and do some practice.