CIS 1057 Computer Programming in C

transcript

IntroductionCIS 1057 Fall 2013 1

Dr. Anwar MamatFall 2013

Acknowledgement: Many slides based on/borrowed from Professor Hugh C. Lauer

Slides include materials from The C Programming Language, 2nd edition, by Kernighan and Ritchie and from C: How to Program, 5th and 6th editions, by Deitel and Deitel)

Course Objectives

• C language programming• Designing, implementing, debugging, etc.

• How the hardware executes C programs• … and other kinds of programs

• Preparation for computational challenges of engineering, scientific, and other professions

• Preparation for upper-level courses in computing

• “Thinking computationally”

• Computing and Programming: a life skill for all technical professionals– http://www.youtube.com/watch?

v=dmM_xDzy2nU

• Thinking Computationally: organizing your engineering/scientific/technical thoughts to be amenable to computational solutions

Why C?

• Because we have to!

• Many situations outside of CS where it is only language or system available

• Small, embedded systems, instrumentation, etc.

• Many “low-level” situations that don’t have support for “high-level” languages

• Operating systems, real-time systems, drivers

Why not C?

• C is very low-level• Data structures must be programmed “by hand”• Operations must be done out in “long hand”• No support for “object oriented” design• Marginal support for higher-level thought processes

• Better alternatives available for technical applications

• Verilog, VHDL, System C – semiconductor design• Matlab, SimuLink – physical modeling• LabView – instrumentation and control• Excel – accounting and statistics• SQL – billing and transactions• …

This Course

• Lectures• C programming language, syntax, semantics, etc.• Common data structures that technical professionals

are likely to need or encounter in C

• Programming Assignments• Write programs to exercise various language

constructs and data structures• Mandatory for passing this course

• Lab Sessions• How to use the system, tools, debuggers, etc.• Practical help from TAs, etc.

This Course (continued)

• Wednesdays and Fridays, 9:30–10:50 AM• Tuttleman 401B

• Weekly Lab Sessions• Mondays: 8:00 AM - 9:50 AM WCHMAN 104

• Midterm exam• Oct. 18

• Review session prior to exam on Oct. 16

Closed book, one 8½-by-11 sheet of prepared notes, no calculators or electronics

Prerequisites

• First-level gen-ed math course

Logistics

• Course web site– http://cis.temple.edu/~anwar/CIS1057Fall2013.html– Blackboard

• Professor’s office Hours– Mondays, 10:00-12:00 AM, or by appointment

(additional hours TBD)– Wachman 414 (215) 204-4207

• Contacts– anwar@ temple.edu

• Teaching assistant– Li, Dawei (TA)

Required Textbook

• Problem Solving and Program Design in C, 7th Edition, Hanly and Koffman

• Reference book:– The C Programming Language, 2nd edition, by

Brian Kernighan and Dennis Ritchie, Prentice Hall, 1988

Bring to all classes and all lab sessions

Textbook Outline• 1. Overview of Computers and Programming

• 2. Overview of C

• 3. Top-Down Design with Functions

• 4. Selection Structures: if and switch Statements

• 5. Repetition and Loop Statements

• 6. Pointers and Modular Programming

• 7. Arrays

• 8. Strings

• 9. Recursion

• 10. Structure and Union Types

• 11. Text and Binary File Processing

• 12. Programming in the Large

• 13. Dynamic Data Structures

• Appendix A,B,C,D,E: the C language reference, the standard libraries

• You will use these a lot!

Ground Rule #1

• There are no “stupid” questions.

• It is a waste of your time and the class’s time to proceed when you don’t understand the basic terms.

• If you don’t understand it, someone else probably doesn’t it, either.

Ground Rule #2

• Help each other!

• Even when a project or assignment is specified as individual, ask your friends or classmates about stuff you don’t understand.

• It is a waste of your time try to figure out some obscure detail on your own when there are lots of resources around.

• When you have the answer, write it in your own words (or own coding style).

Names and Faces

• It is in your own interest that I know who you are.

• Students who speak up in class usually get more favorable grades than those who don’t

• When speaking in class, please identify yourselves

Temple Academic Honesty Policy

• It is a violation of the Temple Academic Honesty Policy to submit someone else’s work as your own.

• It is not a violation of Temple’s Academic Honesty Policy to ask for help!

• Classmates, TAs, friends, mentors, …

• Explanations of things you don’t understand

Additional Help

• Academic Resource Center has Tutors available to assist in Wachman 200.

Questions?

The C Language

• First created to develop Unix – late 1960s• Kernighan & Ritchie, 1st edition – 1978

• ANSI C – 1988• Kernighan & Ritchie, 2nd edition, 1988• Implemented by nearly all C compilers

• C95, C99• Minor additions (to be noted as we get to them)• Most major C compilers

Successors to C

• C++• Developed by Bjarne Stroustrup at Bell Labs

• Major extension of C to support object-oriented programming

• Attempted to preserve syntax and structure of C

• Java• Rewrite of C++ at Sun Microsystems

• Machine independence, portability

• Ability to embed in web pages

• Huge libraries of packages for all kinds of stuff

Your First C Program

#include <stdio.h>

int main () {

printf(″Hello, World!\n″);

return 0;

Fundamental Rule in C

• Every identifier must be declared before it can be used in a program

• Definition:– “identifier”• A sequence of letters, digits, and ‘_’• Must begin with a letter or ‘_’• Case is significant

– Upper and lower case letters are different

• Must not be a “reserved word” — see appendix

• Definition:– “declare”• Introduce an identifier and the kind of entity it refers to• Optionally, define associated memory or program

So where is printf declared?

#include <stdio.h>

int main () {

return 0;

So where is printf declared?

#include <stdio.h>

int main () {

return 0;

Answer: in this file!

#include <stdio.h>

int main () {

return 0;

• A header file• Contains declarations

of names, functions, data, of things defined elsewhere

• E.g., by the system

• Text of the header file is inserted by compiler into your program

• As if you wrote it yourself!

#include <stdio.h>

int main () {

return 0;

• A function declaration• Declares the name and

defines the body of your function

• May take arguments, returns an integer

• main is a special name to the system

• The place where a program “starts”

#include <stdio.h>

int main () {

return 0;

• Body of the function• Defines what the

function “does”• Sequence of

statements• Each does a step of the

function

• Enclosed in curly brackets

•{ }

#include <stdio.h>

int main () {

return 0;

• Call to another function • In this case, a function defined by the system

• Prints some data on standard output

#include <stdio.h>

int main () {

return 0;

• Argument to printf – a constant string• Enclosed in straight double quotes

• Note the new-line character ′\n′ at the end

#include <stdio.h>

int main () {

return 0;

• A return statement• return is a reserved word in C

• main should return zero if no error; non-zero if error

#include <stdio.h>

int main () {

return 0;

• Note that statements typically end with semicolons• So compiler can tell where end of statement is

Questions?

Write, compile, and execute this program in Lab session

What happens to your program …

…after it is compiled, but before it can be run?

Example

#include <stdio.h>

int main () {

printf (″Hello, world\n″);

• Symbol defined in your program and used elsewhere

•main

• Symbol defined elsewhere and used by your program

•printf

Static Linking and LoadingPrintf.c

Printf.o

Librarygcc

Linker

Memory

HelloWorld.c

HelloWorld.o

Loader

a.out(or name of

your command)

Compiling Your Program• gcc HelloWorld.c

• Compiles the program in HelloWorld.c, links with any standard libraries, puts executable in a.out

• You should find HelloWorld.o in your directory

• gcc –o hello_world HelloWorld.c• Same as above, but names the executable file hello_world instead of a.out

• gcc –lrt HelloWorld.c• Searches library named rt.a for functions to link

(in addition to standard libraries)

Compiling Your Program (continued)

• gcc foo.c bar.c help.c• Compiles the programs foo.c, bar.c, and help.c,

links with standard libraries, executable in a.out• You should find foo.o, bar.o, and help.o in your

CIS 1057 Computer Programming in C

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