1. Welcome to Intro to Systems Programming!
CS/COE 0449 (term 2184)
Jarrett Billingsley

2. Administrivia
CS449 (2184)

3. hi you can just call me Jarrett
graduated from Pitt with a (bachelor’s) degree in CS in 2009
I’ve been a “part time” instructor here for almost 2 years
I love teaching
course site: pitt.edu/~jfb42/cs0449
all the stuff I talk about today is on the course site
office: 6148 SENSQ
office Hours: Mon/Wed 12:30-4:15
piazza: Yes
discord: Yes
CS447 (2184)

4. Textbook (?) Practical C Programming (Oualline)
no readings, no exercises
actually I don't really use it at all
it's an adorable time capsule
it's good for teaching about C
but it's not strictly required
CS447 (2184)

5. Grading there is no such thing as attendance labs and quizzes: 15%
several labs
don't worry about the quizzes, they're worth so little
projects: 40%
five projects, so 8% each
time management is a good skill
exams: 45%
2 midterms, 1 (semi-cumulative) final, so 15% each
exact dates of midterms are a bit flexible for your sake
grading scale is a little unusual
must get at least a 75% to get a C, in order to pass
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6. Expectations religious absences are excused: contact me ASAP
students with disabilities should contact the Office of Disability Resources and Services (DRS) if you haven’t already
216 William Pitt Union; ; TTY:
cheating: 0 on assignment first time, fail the course second time.
…but you can work with one partner on projects
inform me ahead of time, and do not share code!
you can also talk about labs, but still no sharing stuff
jokes or comments about sex, gender, race, ethnicity, religion, etc. will not be tolerated
this is not Reddit or 4Chan
this goes for lecture, office hours, chatroom, etc.
other than that… go nuts, idgaf
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7. Teaching philosophy I wanna help you understand!!!!!!
NO QUESTIONS ARE DUMB!!!!!
NEVER BE AFRAID TO ASK THEM!!!!
DON’T STRUGGLE IN SILENCE ON YOUR PROJECTS/LABS!!!!!!!
I trust you!
I try to be accommodating
I don’t think most cheaters are being lazy
but you’re an adult, and are responsible for your actions.
yeah, you could learn all this stuff on your own
you’re paying money to have access to me
I actually get bored just standing up here and talking
be more interactive
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8. I can tell when you cheat :^)
I'm not grading this term but I'll still look at your stuff
If you're confused, don't cheat, ask me for help?
don't wait until you get an F on exam 1
hot tips for not cheating:
don't
cmon, don't
don't post your damn code on github until after the semester
if your enrollment is contingent upon your GPA,
fucking
cheat
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9. Intro
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10. Goals of this course goes hand-in-hand with 447
both teach some similar topics from different angles:
representation of data
organization of memory
how programs really run
the call stack and calling conventions
this course also exposes you to a new programming language, C
it's a good kind of shock, like a splash of cold water
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11. #include <stdio.h> int main() { printf("Hello, world!\n");
splashhhhh 💦
well here's some C
#include <stdio.h>
int main() {
printf("Hello, world!\n");
return 0; }
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12. Falling down the rabbit hole
if you compile that C program, you don't get a "class file"
you get a real, honest-to-god executable program
but...
what does that executable program file contain?
what happens when you run it?
how does the program actually make things happen?
how do programs control the computer hardware?
how do multiple programs run at the same time?
that's what this course is all about.
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13. Tools of the trade
this course also exposes you to a lot of common tools
ssh
ftp
gcc
gdb
make
these are used allllll the tiiiiiiiiime in all areas of programming
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14. Appearances can be deceiving
C's syntax (the symbols and words used to represent a program) might remind you of Java
but it sure doesn't behave the same way
control structures (if-elses, loops, switches) are pretty similar
but just about everything else is… different in some way
int x = 5;
printf("The value of x is: " + x);
let's see what it prints
oh.
webcomicname.com
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15. The training wheels are off
C is weird and prickly and unforgiving
it's also like 45 years old
maybe these traits are reminding you of a person
BUT: C helps you deeply understand how computers work because:
virtually every CPU architecture around today has been designed to run programs written in C
understanding C is understanding how modern computers work.
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16. Coevolution
like this flower and the weird bird that matches it, C and modern CPUs have coevolved
C became popular
so they made CPUs that could run C programs fast
so C became more popular, etc…
most of the operations in C have, like, a direct mapping to a CPU operation
which you will/have learned about in 447
there's a lot of back-and-forth between these courses!
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17. Blobject-bloriented blprogramming
Java is OOP: "object-oriented programming"
that's fine, but...
if someone tells you that their way of thinking will solve all your problems, they're lying
(this is general life advice)
part of being an "engineer" is knowing what tool is appropriate for the situation
and OOP is not always that tool
OOP
literally every programming problem
Java
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18. Procedural programming
a procedure (or function as most people call them today) is an ordered sequence of computational steps
functions can call one another
the callee runs until it finishes
then control goes back to the caller
that's... it
revolutionary huh
the 1970s were a simpler time C
OOP
Java
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19. A product of its time
when C was developed, computers hadn't… really settled down yet
things were weird
kind of the "cambrian explosion" of CPU design
also computers were far less capable
they had to trim a lot of "luxury" features like "compiler errors"
C takes a very odd approach to platform independence
basically most stuff is "undefined"
this makes it flexible to a fault
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20. before each integer type
As an example…
let's look at C's primitive data types:
Integers
char
short
int
long
long long*
Reals
float
double
long double*
you can also stick
signed or
unsigned
before each integer type
*C99 and newer only...
yaaaaaaaaaaay...
how big are these? it's platform dependent
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21. Um, what about strings? hahahaha oh geez
strings are a fancy high-level abstraction!!! what a luxury
char is an integer which happens to be used for text, uh, sometimes
depending on what (human) language you're talking about
and what system you're running on
char is really defined as the smallest addressable integer type.
these days that usually means a byte
but that's not guaranteed by the C spec.
so don't assume char always has something to do with text
it might just be some bytes
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22. Where we're going first part of the course is C
then we talk about programs and memory
last part is operating systemy stuff
get ready for it!!!!
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