COS 217

• Course Info
• Lectures/Precepts
• Assignments
• Exams
• Policies

Midterm Exam

Wednesday, October 9, 10:00am - 10:50am

The exam will be given in-person on-paper live in the following locations — double-check that you're attending in the right room for your precept section!

• Friend 004: T/Th 1:30 precepts (P05, P06)
• Friend 008: T/Th 3:30 precepts (P07, P10)
• Friend 101: Everyone else — M/W precepts (P01, P02), T/Th 12:30 precepts (P03, P04, P09), T/Th 7:30 precept (P08)

Students who have testing accommodations should coordinate with lead preceptor Christopher Moretti (cmoretti@cs.princeton.edu) to confirm alternate times, locations, and/or conditions.

Rules

You will have fifty minutes to complete the exam.

This will be a closed-book, closed-note exam, with the exception that a single one-sided study sheet will be allowed. The exam will emphasize application of concepts and not memorization, so you will be provided with information such as manual pages, C operator precedence tables, etc. if they are necessary. No electronic devices will be permitted to be used during the exam. No communication with any person will be permitted, with the exception of the instructors who will be available for clarifying questions outside the exam room. Some students may be taking this exam at a different time, so use discretion in discussing the contents of the exam with anyone until the sample solution has been posted.

The Princeton University Honor Code covers this exam. You will be required to write out in full and sign an honor code pledge that you have abided by these exam rules and restrictions. Any suspected violations must be reported to honor@princeton.edu

Topics

You will be responsible for material from the course through week 5 (and, thus, excluding Monday/Tuesday of midterms week), including the content of required readings, lectures, precepts, and assignments 0, 1, and 2. All questions will assume the ArmLab/Linux/C/gcc217 environment unless otherwise stated.

Major topics include:

1. Number Systems
   • Binary, octal, decimal, hexadecimal number systems
   • Unsigned integers: finite representation and operations
   • Signed integers: finite two's complement representation and operations
   • Overflow
2. C Programming (ANSI C89 / ISO C90)
   • The program preparation process: preprocess, compile, assemble, link
   • Program structure: multi-file programs using header files
   • Statements
   • Operators
   • Input/output: getchar(), fgetc(), putchar(), fputc(), gets(), fgets(), puts(), fputs(), scanf(), fscanf(), printf(), fprintf()
   • Data types
   • Basic variable declarations and definitions
   • Process memory layout: text, stack, heap, rodata sections
   • Constants: #define, const variables, enumerations
   • Basic function declarations and definitions
   • Arrays and pointers, call by reference, arrays as parameters, strings
   • Command-line arguments
   • Structures
   • Dynamic memory management: malloc(), calloc(), realloc(), and free()
   • Common memory/pointer errors: dereference of uninitialized, dangling, or NULL pointer, memory leak, double free
3. Programming techniques and tools
   • git and source code management
   • make and build management
   • Testing
   • gdb and debugging
   • Deterministic finite-state automata (DFA)

Questions from Previous Semesters

A good way to practice for the exam is to go over questions from previous COS 217 midterm exams. Be aware that both the content of the course and the format of the midterm do change over the years, so not all questions are guaranteed to be 100% relevant, or good practice for this year. If you have any questions about whether the content of a question would be fair game for this year, please ask on Ed.

• Sample questions and answers
• Exclusions - questions on topics we haven't covered, if any
• Topics index for the sample questions

Q&A

There will be a Q&A session, Monday 10/7 at 7:30pm in Computer Science 104. This session will cover midterm review questions students ask, including working midterm problems from the released archive.

After the exam

There will be precepts on the Wednesday and Thursday of exam week!

There will be no lectures, precepts, or office hours between Friday 10/11 and Sunday 10/20, inclusive. Enjoy your break!

We will keep up with Ed for questions about Assignment 3, but we will not check it as often as we do during normal weeks.