1. C Language: Introduction
C Programming
CISY 238
Bill Klinger
C Language: Introduction

2. C Language: Introduction
RVCC Tutoring Center
Room S-020-C
C Language: Introduction

3. C Language: Introduction
Outline
Computer languages
C Background
Programming
UNIX environment
Editor
C fundamentals
Getting started
C Language: Introduction

4. C Language: Introduction
Computer Languages
Computers
powerful
complex
use simple instructions
Language development
machine language
assembler
high level languages
4GLs
C Language: Introduction

5. Evolution of Computer Complexity
C Language: Introduction

6. C Language: Introduction
Early Languages
Fortran
Formula translation
Scientific applications
COBOL
Common Business Oriented Language
Business / data applications
C Language: Introduction

7. C Language: Introduction
Language Explosion
Algol
Designed with programming concepts in mind
Basic
The first interactive language
Simula
Extended Algol to facilitate simulations, first O-O language
Snobol
Specially designed to handle string manipulation
LISP
Used in artificial intelligence applications
PL/1
Language for everyone (therefore no one)
C Language: Introduction

8. C Language: Introduction
Created by Dennis Ritchie
early 1970’s
Bell Labs
C comes after B
C++ comes after C
Design principles
high level language
allow for detailed control of the system
C Language: Introduction

9. C Language: Introduction
UNIX implemented in C
Distributed to universities
Becomes commercial success
widely available
efficient
C/C++ still the language of choice for ‘serious’ applications
C Language: Introduction

10. C Language: Introduction
C Language Usage
systems programmers (drivers)
operating systems (Linux, UNIX, Windows, et.al.)
embedded systems
real-time systems
games
applications
education
C Language: Introduction

11. C Language: Introduction
ANSI C
Standard established
to ensure common language set by vendors
allows programs to ‘port’ to different computers
ANSI
American National Standards Institute
has established standards for many languages
C Language: Introduction

12. C Language: Introduction
A Word About C++
Extends C
all of C in C++
C++ adds object oriented programming
incorporates classes from Simula
does some ‘clean up’
C Language: Introduction

13. C Language: Introduction
Programming
The process of translating needs (requirements) into directions a computer can execute.
C Language: Introduction

14. C Language: Introduction
Programming
An art
there is a beauty in good programs
it is a creative process
A science
there is certainty in programs
programming requires precision
computer will do what it is instructed to
lather – rinse – repeat
C Language: Introduction

15. C Language: Introduction
The Process
Write the code
called ‘source code’
written using an editor
Compile the code
using a compiler
creates object modules
Link the objects
put together the pieces
creates the executable
Test / debug
C Language: Introduction

16. C Language: Introduction
The Process
Write the code
use vi, pico, notepad, TextPad, or some editor
Compile
use cc on UNIX
Link
cc will also link
Test / debug
C Language: Introduction

17. C Language: Introduction
UNIX Editors vi
available on all UNIX / Linux systems
primitive but powerful
pico
simpler than vi
less powerful
C Language: Introduction

18. C Language: Introduction
The C Language
small, efficient and powerful
easy to learn (sort of)
precise computer control
no hidden mechanisms or magic
C Standard Library
C Language: Introduction

19. C Language: Introduction
C Source File Creation
Use text editor (vi, emacs, pico, TextPad, NotePad, etc.) to create a file
for C language, the file must have a .c suffix
C Language: Introduction

20. C Executable Program Creation
C is a compiled rather than an interpreted language, the .c source file can not be directly executed like a shell script
compile using the C compiler cc: $ cc program.c ---> a.out (where a.out is the default executable file name)
run program by entering its name: $ a.out
can choose a different name for the executable: $ cc -o myprogram program.c ---> myprogram
- or: $ mv a.out myprogram
C Language: Introduction

21. C Language: Introduction
C Source File
// a basic program
#include <stdio.h>
main() {
printf(“Hello World”); }
hello.c
C Language: Introduction

22. C Language: Introduction
C Source File Contents
main function; main tells where the program starts, one and only one main
a left brace { is the beginning and a right brace } is the end of a function or code block
parentheses ( ) indicate a function definition
C Language: Introduction

23. C Language: Introduction
Printing
Use the ‘printf’ statement
Form
printf(“<string>”);
Note:
string is enclosed in quotes
C statement ends in semicolon
C Language: Introduction

24. C Language: Introduction
Printing
printf ‘prints’ a stream of characters
whatever is in <string> is output
no automatic “new lines”
Use \n to print a new line character
printf does not actually print to a printer
goes to UNIX standard output
default is to terminal
C Language: Introduction

25. C Language: Introduction
Variable Basics
Must declare variables before using them
e.g.
int age;
int sum, average;
Use meaningful names !
C Language: Introduction

26. C Language: Introduction
Statement Basics
Assignment indicated with ‘=‘
e.g.
sum = 5 + 4;
sum = myage + your age;
age = age + 1;
Note:
each statement ends in a semicolon‘;’
= does not mean arithmetic equality
C Language: Introduction

27. C Language: Introduction
C Source File
// a simple program that prints
// the number of fruit
#include <stdio.h>
main() {
int oranges;
int apples;
int fruit;
oranges = 5;
apples = 17;
fruit = oranges + apples;
printf(“We have %d pieces of fruit”, fruit); }
fruit.c
C Language: Introduction

28. C Language: Introduction
Let’s Get Started
Do Hello World program together
Exercises listed on web
C Language: Introduction