CMSC 246: Systems Programming

General Information

Instructor:

Lecture Hours: MW 10:10AM - 11:30AM
Room: Park 336
Lab: Park 231 Mo 1:10PM - 2:30PM (Attendance in Lab is REQUIRED)
Office Hours: T 10:00-11:00AM, W 1:00-2:00PM, or by appointment

Laboratories:

Lab Assistant: The TA for the course is Sara Golobish. She will be available in the CS labs (either Park 230 or Park 231) every Thusday and Thursday evening 7-9PM (except as noted below). Class assignments will typically be due either Friday evening. Please be aware that there will be several other TAs in the lab at this time. Try to find Sara for 246 questions.

On the following dates, the hours of the lab assistant will be other than the norm:

• Oct 1: 8-10pm
• Oct 29: Moved to Wed Oct 30 7-9 PM

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Texts & Software

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Syllabus

Course Description: This is a course in systems programming using the C programming language in the Linux environment. C undergirds the world of modern computers and runs on anything. Learning C will also teach you how a computer really works under the hood and it will power your knowledge of programming and system building on any platform.

A secondary goal of this course is to give you a chance to learn some fundamental technologies in widespread use. As a computer scientist, you will be expected to know about Makefiles, version control, and command-line execution in the Linux environment.

By the end of this course, you will be able to…

• Write standalone programs in the C programming language
• Understand computer memory management and pointers
• Work with linked structures (lists, trees, and graphs)
• Use the Linux command line
• Become familiar with programming tools and environment in Linux

During the course, you will…

• Code lots of C programs
• Setup and use Make files, and other Linux tools
• Learn how to debug
• (Possibly) learn keep your work safe with Git

Course Philosophy: In order to learn any programming skill, you must simply do it. Reading a book or watching me code will not help you get better. This course is thus programming-intensive. You will be expected to spend a significant amount of time weekly (6-8 hours) outside of class programming to complete the homework assignments. If you run into a snag, the programming burden may prove to be even higher. Of course, programming is fun, so the time should fly by.

Class time in CS246 will be spent primarily working with peers to solve small programming problems, conduct peer reviews, and complete other exercises. It is expected that you complete the reading before class and come with questions; I will try to avoid spending large chunks of class time repeating what the book says so well.

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Important Dates

• First lecture: Sept 4
  
• Exam 1: Oct 9
  
• Exam 2: Nov 20Nov 13
  
• Exam 3: Self-scheduled during exam week.

Assignments

• Assignment #1 (Due on Friday, Sep 13): Click here for details.
• Assignment #2 (Due on Friday, Sep 20): Click here for details.
• Assignment #3 (Due on Friday, Sep 27): Click here for details. (for making large arrays, please see This program)
• Assignment #4 (Due on Friday, Oct 4): Click here for details. If you are attending Grace Hopper send me an email for a free 2 day extension.
• Assignment #5 (Due on Friday, Oct 25 Sunday Oct 27 by 5pm): Click here for details
• Assignment #6 (Due Sunday Nov 3 before midnight): Click here for details 10/29: I updated slightly the submission directory. This change means that the submit program will not work.
• Assignment #7 (Due Sunday Nov 10 before midnight): Click here for details
  • large data file
  • small data file
• Assignment #8 (Due Wednesday, Nov 27 before midnight): Monday Dec 2 prior to MidnightClick here for details Due date changed
• Assignment #9 Saturday, December 14, before midnight Click here for details

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Labs

• Lab 1: Sept 9 Click here for details.
• Lab 2: Sept 16 Click here for details. Also Emacs
• Lab 3: Sept 23 Click here for details.
• Lab 4: Sept 30 Click here for details.
• Lab 5: Oct 07 Click here for details Pre-midterm review.
• Lab 6: Oct 21 Click here for details Words, words, words.
• Lab 7: Oct 28 Click here for details Breaking up Airports.
• Lab 8: Nov 04 Click here for details GDB!.
• Lab 9: Nov 18 Click here for details Circular linked lists
• Lab 10: Nov 25 Click here for details writing shell scripts.
  Here are my solutions for 2-7.
  • Q2
  • Q3
  • Q4
  • Q5
  • Q6
  • Q7

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Lectures

• Week 1
  Sept 4 Introduction & administrivia. Meeting Linux & C: WIMP vs CLI, basic shell commands. a brief history of the evolution of C, a quick overview of C (aka C for Java programmers), writing, compiling, and running C programs.
  
  Overview of C: Printf() and scanf(), conditionals and loops. Writing basic C programs.
  Lecture materials
  • Slides
  • Hello world
  • Obfuscated C
  • Simple printing and booleans
  
  Assignment #1 (Due on Sep 12): Click here for details.
  
  Read: Chapters 1-6 from King. Chapters 1-4 from Shotts.

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• Week 2
  
  Continuing overview of C: scanf, printf, loops, arrays, types, pass by value.
  ctype library (and more generally generally using libraries)
  Read: Chapters 7-9 from King. Chapters 5 from Shotts.

Sep 9 Materials
• Slides
• tprintf.c
• c2f.c (final version)

Sep 11 Materials
• Slides
• types.c Shows interchanability between int and char
• c2ftable.c a table of celcius to fahrenheit conversions
• c2floop.c The scanf looping problem
• shoutj.c Program to take user input and upper case it.

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• Week 3
  
  Continuing overview of C: more with arrays. More with C libraries. .h files. UNIX: paths, which and redirection
  Read: Chapters 7-9 from King. Chapter 5-6 from Shotts.

Sep 16 Materials
• shoutc.c Uppercase, C style. Chars as numbers. Pointer math.
• sprint.c Printing of uninitializied portions of char array.
• stddev.c Random number generation (srand and rand), functions in C. Linking in libm gcc -lm stddev.c

Sep 18 Materials
• c2fsafe2.c c2fsafe2.h c2f using only getchar. Also, use of local .h file
• rmcm.c 2-d arrays, row major allocation of 2-d arrays, more pointer math. Issue encountered in class fixed.
• p1.c Alternate form of main for getting command line arguments
• p2.c Reading from stdin when stdin is not the keyboard for instance a.out < p2.c or cat p2.c | a.out

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• Week 4
  
  Continuing overview of C: references, pointers and arrays. functions and pass by reference. string.h .h files and Makefiles UNIX: paths, which and redirection
  Makefiles (simple) makefile tutorial
  Read: Chapters 11-13 from King. Chapter 6-8 from Shotts.

Sep 23 Materials
• timer.c getting the runtime for a function
• ttest.c Compute the value of the T test. Then looking meaning using a T-Test table.
• p1.c Global Variables
• p3.c Pass by value in C
• p7.c Try to return an array from a function. Not allowed.
• strcatovr.c Using strcat from the string.h library and the problem of writing beyond the end of the array.

Sep 25 Materials
• strokex.c Example of strtok from string.h library
• mystrtok.cMy implementation of the strtok function. This one is more limited than teh library function in that it tokenizes on a single character
• p1.c Read from a test file. This has several slightly different reading methods> usage a.out filename [1-5]
• p2.c Timing of just writing to array. Poiter vs array style. Usage a.out [1,2] where 1 is array-style and 2 is pointer
• Makefile A very simple makefile. This makefile assume that tests files are in the same directory ttest.c ttest.hbasestats.cbasestats.h
• Makefile2 An equivalent makefile, but with variables
• makefile tutorial

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• Week 5
  
  Continuing overview of C: multidimensional arrays and pointers thereto. Heap space and stack space. Recursion. Other topics from chapters 1-14, Macros and the preprocessor UNIX: permissions and processes.
  Read: Chapters 14 from King. Chapter 9-10 from Shotts.

Sep 30 Materials
• p3.c passing multi dimensional arrays into functions
• p4.c creating multi dimensional arrays that vary in length.
• binsearcha.c Recusrion, binary search and the stack

Oct 2 Materials
• istail.c nottaillong.c Doing a lot of recusrion. Change the stack size using ulimit -s unlimited
• p2.c l04.c strcpy and strcat. p2 cwas not discussed in class. It has lots of examples. l04 includes the use of #if to condifitionally include / exclude some code (this is a change from what I showed in class).

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• Week 6
  Review and Midterm 1
  October 7 Materials
  • p1.c Implementing a logging system using defines.
  • aaa.c The inadvisability of casting pointers to a different type
  • p3.c A couple of trace c output of the c program
  • atof.cConvert string to float. (You should really use strtof from stdlib.h).

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• Week 7
  
  c: Structs, unions and enumsetc Unix: regular expressions!
  Read: Chapters 16 from King. Chapter 19 from Shotts.

Oct 21
• q1.c Midterm Q1
• q2.c Midterm Q2
• q3.c Midterm Q3
• q4.c Midterm Q4
• q5.c Midterm Q5
• typedeff.c money typedef
• weather.c weather & structs. Includes incorrect usage (parseA) and correct (parseB).
• Regular Expressions base expressions   character classes

Oct 22 Materials
• sunion.c Simple use of union conparing storage required by union and equivalent struct
• countn.c a complete implementation of Mondays lab
• weather.c Not shown in class. This creates a structure containing structures to hold the temperature data set.
• enumunion.c Using enum, union and struct to store string and numbers in a single array.
• wmoney.c Wizard money

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• Week 8
  
  c: Dynamic memory allocation
  Unix: Archiving
  Read: Chapters 17 from King. Chapter 18 from Shotts.

Oct 28
• rot13 === tr n-za-m a-z
• passbyval.c pass by value discussion
• reader1.cRead a file, line by line into dynamically allocated memory
• valgrind --leak-check=full --show-leak-kinds=all --track-fds=yes EXECUTABLE
• reader2.c Revised version of reader1.c tha deals with the issues flagged by valgrind

Oct 30 Materials
• Midterm 2 moved to Nov 13
• towers of hanoi challenge Beat my 206 students and get a small amount of extra credit.
• reader1.cRead a file, line by line into dynamically allocated memory, along with dynamically allocate array to hold everything
• copyarray.cDeep and shallow array copies. More with free
• In class I mentioned that the book recommends a style of using malloc. My memory of the book was faulty. What the book recommends is:

  	      int* p = malloc(sizeof(*p));
  	    

  In other words, allocate space for the size of the thing pointed to by p. For more discussion, see the top of page 452.

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• Week 9
  
  c: Dynamic structures, function pointers:
  Unix: network information, text processing:
  Read: Chapters 17 from King. Chapter 16 and 20 from Shotts.

Nov 04
• myspeedbash script for getting the transfer speed of a file
• easysort.cSimple use of qsort
• weather2.c weather data reader using structs within structs. All in single file
• weather5sort.c WeatherDataSort.cWeatherDataSort.h weather data, broken up into struct and driver groupsings along OO style lines. Also, sorting weather data using qsort
• weather5sel.c WeatherDataSel.cWeatherDataSel.h weather data, broken up into struct and driver groupsings along OO style lines. Changed for writing a semi-generic selection method, that allows user to write a qsort like comparator method that is passed into the selection method
• MakefileMy makefile for the day

Nov 06
• pscptiny bash script for using scp. Uses bash command line args
• stack.cC implementation of a stack ... closely follows King
• queue.cA queue implementation that closely follows stack
• queuevoid.cA queue implementation using all void* pointers to make it full generic. This implementation is in no way tied to an underlying type, so it can, at the same time, store pretty much anything.

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• Week 10
  
  Review and midterm 2
  In class answers Questions with answers for the "in class" questions.

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• Week 11
  
  c: Bitwise Operations; King ch 19 Huffmann codes
  Nov 18
  • midterm with answers.
  • reading and writing to files
  Nov 20
  • lots of examples of bit manipulations.
  • printing all of the bits in an arbitrary object Worked on in groups in class

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• Week 12
  
  c: a little more with bits, King ch 19 Unix: bash scripting: king ch 24-29
  Nov 25
  • system report script.
  • simple use of arrays.
  • ping and who script.
  • c program copy the value of a long.Do it bit by bit

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• Week 13
  
  In the beginning; text processing
  Dec 2 discussion of sections 1-5 of "in the beginning was the command line"
  Dec 4 -- Text Processing
  • 3 different text search algorithms. Brute Force, Boyer-Moore, and Knuth-Morris-Pratt.

Course Policies

Communication

Attendance and active participation are expected in every class. Participation includes asking questions, contributing answers, proposing ideas, and providing constructive comments.

As you will discover, I am a proponent of two-way communication and I welcome feedback during the semester about the course. I am available to answer questions, listen to concerns, and talk about any course-related topic (or otherwise!). Come to office hours! This helps me get to know you. You are welcome to stop by and chat. There are many more exciting topics to talk about that I won't have time to cover in-class.

Please stay in touch with me, particularly if you feel stuck on a topic or assignment and can't figure out how to proceed. Often a quick e-mail, phone call or face-to-face conference can reveal solutions to problems and generate renewed creative and scholarly energy. It is essential that you begin assignments early.

Grading

There will be 6-8 assignments, weighted equally in the final grading (see below).  Assignments must be submitted according to the instructions provided in each assignment.

At the end of the semester, final grades will be calculated as a weighted average of all grades according to the following weights:

Exam 1: 16%
Exam 2: 16%
Exam 3: 18%
Lab Attendance: 10%
Assignments: 40%
Total: 100%

Incomplete grades will be given only for verifiable medical illness or other such dire circumstances.

Technology in the classroom

The class meetings/lectures will be a place to learn the concepts that are a part of the syllabus. I will, in the course of a lecture, write code on the board, and/or even do some live coding in class. The objective of this is to illustrate to you how to go about applying the concepts in practice. It is NOT a place for you to open your laptops and start to code with me. In fact, you are encouraged NOT to bring your laptops to class to use them for any purpose. It is distracting to other students. Phone (smart or otherwise) and tablet use during class meetings is also strongly discouraged. Listen, understand, ask questions, and take notes in a notebook if you need to. You will learn more! You will be doing coding in the labs under my supervision.

The assignments in this course are a place for you to exercise your learning of the concepts and apply them in actual working programs. The best way to get the most of of this course is to try out and code the concepts learned in the class (outside the class!). Do not be afraid to try things! This will improve your understanding and raise questions that you should feel free to bring forward in class. A quick word of advice: stay abreast of the material covered in class, and start your assignments on the day they are announced.

ALL work submitted for grading should be entirely YOUR OWN. Sharing of programs, code snippets, etc. is not permitted under ANY circumstances.

Submission, Late Policy, and Making Up Past Work

Exams

There will be three exams in this course.  The exams will be closed-book and closed-notes.  The exams will cover material from lectures, homeworks, and assigned readings.

Study Groups

I encourage you to discuss the material and work together to understand it. Here are some thoughts on collaborating with other students:

• The readings and lecture topics can be group work. Please discuss the readings and associated topics with each other. Work together to understand the material. I highly recommend forming a reading group to discuss the material -- I will explore many ideas and it helps to have multiple people working together to understand them.
  
• It is fine to discuss the topics covered in the homeworks, to discuss approaches to problems, and to sketch out general solutions. However, you MUST write up the homework answers, solutions, and programs individually without sharing specific solutions, mathematical results, program code, etc.  If you made any notes or worked out something on a white board with another person while you were discussing the homework, you shouldn't use those notes while writing up your answer.
  
• Under ABSOLUTELY NO circumstances should you share computer code with another student, printed, electronic, or otherwise.  Similarly, you are not permitted to use or consult code found on the internet for any of your assignments.
  
• Exams, of course, must be your own individual work.

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Links

Learning Accommodations

This class may be recorded.

Created on August 1, 2019.