CGS 3460 PROGRAMMING USING C
Spring 2007
Instructor: Rong Zhang
TAs: Ting Chen and Sungwook Moon
Goals
• We will learn– Read: Understand programs written in C language– Write: Design and implement programs using C language– Compile: Use compiler to convert C code into executable file
under UNIX– Execute: Run corresponding code to get results – Debug: Identify and fix syntax and semantic errors in C code.
• Appropriate for– Technically oriented people with little or no programming
experience – Experienced programmers who want a deep and rigorous
treatment of the language
New View of Computers
• From a programmer’s viewpoint– Computers are tools– A computer program turns raw data into
meaningful information– A program is the driving force behind any job
that any computer does• A program is a list of detailed instructions• These instructions are written in certain
programming language
Available Programming Languages
• Machine Languages• Assembly Languages• High-level Languages
– C/C++– COBOL– Pascal– BASIC– Fortran– JAVA– Etc.
Machine Languages
• System of instructions and data directly understandable by a computer's central processing unit.
• Example:100011 00011 01000 00000 00001 000100
000010 00000 00000 00000 10000 000001
000000 00001 00010 00110 00000 100000
• Every CPU model has its own machine code, or instruction set, although there is considerable overlap between some
Assembly Languages
• Human-readable notation for the machine language that a specific computer architecture uses representing elementary computer operations (translated via assemblers)
• Example:load hourlyRatemul workHoursstore salary
• Even into the 1990s, the majority of console video games were written in assembly language.
High-level Languages
• Higher level of abstraction from machine language – Codes similar to everyday English
• Use mathematical notations (translated via compilers) – Example:
salary = hourlyRate * workHours
• Make complex programming simpler
Why Programming using C
• Initial development occurred at Bell Labs in early 70’s by Ritchie
• General-purpose computer programming language – high-level assembly – Simplicity and efficiency of the code
• The most widely used programming languages– Commonly used for writing system software– Widely used for writing applications– Hardware independent (portable)
• Great influence on many other popular languages
Textbooks
• RequiredProgramming in C (3rd Edition) by Stephen Kochan.
ISBN: 0672326663. Link for the book from amazon:
http://www.amazon.com/gp/product/0672326663
• Recommended Reading Absolute Beginner's Guide to C by Greg Perry. ISBN:
0672305100. Link
http://www.amazon.com/gp/product/0672305100
Outline of the Course – I• Introductions
– Familiarization with programming environment, telnet / SSH Secure Shell, ftp / SSH Secure File Transfer, UNIX, Compiling / gcc
• C program structure• Basic data types and variables declaration• Arithmetic expressions and operators• Control statements.
– Conditional statements – The while loop – The do while loop – The for loop – The if else statement– The switch statement – The break statement – The continue statement
Outline of the Course – II• Formatted Input and Output • Arrays and Strings• Functions
– Declarations – Calling
• Pointers • Struct, Union, Enums • Preprocessor• * Advanced Material
– Debug using gdb– Arrays and Pointer Arithmetic– Binary Trees – Link Lists– Recursive Functions
* may be adjusted according to time and interests of students
Grading Scale
• You earn your grade• Final grade is calculated according to the
following scheduleHome works 30%Quizzes 20%Mid-term exam 20%Final exam / Project 30%
• Grade scale is:A(100-90),B+(89-85),B(84-80),C+(79-75),C(74-70),D+(69-65),D(64-60),F(59-0)
Policies
• Attendance and Expectations
• Homework Policies
• Make-up Exam Policy
• Other Policies– Re-grading
• Course is on WebCT
http://lss.at.ufl.edu/services/webct/
History - I
Konrad Zuse's Z1 Circa 1936
• The first freely programmable binary computer
• Konrad Zuse's in Germany
• Innovations– Floating-point arithmetic– High-capacity memory– Modules or relays
operating on the yes/no principle.
From http://inventors.about.com/library/blcoindex.htm
History - II
• The first electronic-digital computer
• Iowa State University • Innovations
– A binary system of arithmetic
– Parallel processing– Regenerative memory– Separation of memory
and computing functions
Atanasoff-Berry Computer
From http://inventors.about.com/library/blcoindex.htm
History- III
• ENIAC I (Electrical Numerical Integrator And Calculator)
• John Mauchly and J Presper Eckert
• 500,000 dollars• Thousand times faster
– 17,468 vacuum tubes– 70,000 resistors– 10,000 capacitors, etc– 800 square feet floor space– 30 tons– 160 kilowatts of electrical power
The ENIAC 1946
From http://inventors.about.com/library/blcoindex.htm
History- IV
• First home computer– Scelbi – Mark-8 Altair – IBM 5100 Computers
• 1974/1975• Altair
– 8080 CPU– 256 Byte RAM card– $400– The consumer needs to put them
together, make it work and write any needed software.
– Paul Allen and Bill Gates develop BASIC for the Altair 8800
From http://inventors.about.com/library/blcoindex.htm
Mark-8 Altair
History- V
• Personal computer– IBM PC in 1981– Apple Macintosh in
1984 – Microsoft Windows 1.0
ships in November, 1985
– Network
http://www.pbs.org/nerds/timeline/
original IBM PC 1981
Operating System
• What is OS?– A program that allows you to interact with the
computer -- all of the software and hardware• With a command-line operating system (e.g., DOS)• With a graphical user interface (GUI) operating system (e.g.,
Windows)
• Two major classes of operating systems– Windows
• Nice interface, easy to learn
– Unix• reliable timesharing operating system
Why we choose UNIX
• Powerful – Multi-user operating system– Good programming tools
• Most heavy-duty database management systems started out on Unix
• Flexible – Thousands of tools that can be combined and
recombined.
• Reliable – Unix is hard to crash.
How to Access a UNIX Machine
Your personal computer
(client)
grove.ufl.edu
(server)
telnet / ftp
telnet: allows you to connect to other computers and use softwares thereftp: allows you to retrieve files from other computers.
Telnet
• TELetype NETwork– A network protocol used on the Internet / LAN
– By extension, refers to the program which provides the client part of the protocol
• Once connected– Log on as a regular user with access to
• application / software• data
• A Telnet command request looks like this – telnet grove.ufl.edu
FTP
• File Transfer Protocol– A network protocol used on the Internet / LAN– Allow to transfer files to and from remote
computers
• A ftp command request looks like this – ftp grove.ufl.edu
SSH
• Why SSH
Figures from http://www.suso.org/docs/shell/ssh.sdf
• Download SSH– http://www.openssh.org/
More about SSH
• Recommendation for Windows– Putty as telnet tool
• http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
– WinSCP as ftp tool• http://winscp.net/eng/download.php
• Other choices– ftp, telnet using command line in windows– Other softwares
• Core FTPhttp://www.coreftp.com/download.html
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Preprocessor: interact with input/output of your computer
You will see this at the beginning of nearly all programs
Tells computer to load file named <stdio.h>
<stdio.h> allows standard input/output operations
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Start point of the program
Preprocessor: interact with input/output of your computer
C programs contain one or more functions, exactly one of which must be main
int means that the function main will "return" an integer value
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Start point of the program
Preprocessor: interact with input/output of your computer
Start and finish of function
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Printing a line of Text
Start point of the program
Preprocessor: interact with input/output of your computer
Start and finish of function
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Printing a line of Text
Start point of the program
Preprocessor: interact with input/output of your computer
Start and finish of function
New line character
Your First Program
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
Printing a line of Text
Start point of the program
Preprocessor: interact with input/output of your computer
Start and finish of function
Finish and return value 0
A way to exit a function
It means that the program terminated normally in this case
Comments for programs
• Why need comments– Good habit– Readable to others– Remind yourself
• How to comment– /* … */– // …
• Effects on compiler• Examples
Compiler
• What is compiler– A computer program (or set of programs) that
translates text written in a computer language ( the source code) into another computer language (most time the executable file)
• Why we need a compiler
• Available C compiler in UNIX system: gccgcc sourcefile.c –o exefile.exe
Text Editor in UNIX
• Edit your code Using wordpad, MS word on your personal computer– Need to transfer your program to UNIX
machine using ftp
• Edit your code in UNIX using– vi– pico– emacs
Procedure
This is your C program. Type the code in any standard text editor, and save it as helloworld.c. Transfer it to grove.ufl.edu if necessary
#include <stdio.h> int main() { printf("Hello World\n"); return 0; }
helloworld.c
C-compilerType gcc helloworld.c –o helloworld.exe
to compile helloworld.c into helloworld.exe using the gcc compiler
0011 0000 1010 01101100 0110 1011 01011010 1110 0110 1110
helloworld.exe The gcc compiler generate corresponding executable code named helloworld.exe. The computer can execute this machine readable code if you type ./helloworld.exe