Chapter 1: Introduction

C Programming
Essentials
Unit 1: Sequential Programming
CHAPTER 1: INTRODUCTION
DR. ERIC CHOU IEEE SENIOR MEMBER

About This Course
Instructor: Dr. Eric Chou
Textbook:
The C Programming Language
by Kernighan, Ritchie. Second Edition

Topics
•Introduction to Programming in C
•Data Type, Operators, Basic I/O
•Conditional Expressions, Control Flow
•Loops
•Functions, Program Structure and Recursion
•Pointer and Arrays
•Structure, Union and Enum
•Dynamic allocation
•Storage Classes
•Pre-processor, File Handling, Exceptions, Math library
•Basic Algorithms: Searching, Sorting

Standard C
•Standardized in 1989 by ANSI (American National Standards Institute) known as
ANSI C
•International standard (ISO) in 1990 which was adopted by ANSI and is known
as C89
•As part of the normal evolution process the standard was updated in 1995
(C95) and 1999 (C99)
•C++ and C
• C++ extends C to include support for Object Oriented Programming and
other features that facilitate large software development projects
• C is not strictly a subset of C++, but it is possible to write “Clean C” that
conforms to both the C++ and C standards.

Elements of a C Program
•A C development environment includes
• System libraries and headers: a set of standard libraries and their header files. For example see
/usr/include and glibc.
• Application Source: application source and header files
• Compiler: converts source to object code for a specific platform
• Linker: resolves external references and produces the executable module
•User program structure
• there must be one main function where execution begins when the program is run. This function
is called main
• int main (void) { ... },
• int main (int argc, char *argv[]) { ... }
• UNIX Systems have a 3rd way to define main(), though it is not POSIX.1 compliant
int main (int argc, char *argv[], char *envp[])
• additional local and external functions and variables

About C
•GNU : GNU's Not Unix, We use MinGW version of gcc.
• GNU C: gcc is a standard compiler
•C is non-portable (Suitable for machine-native code development)
• Terms: Compiler (human -> machine [once]), Interpreter
(instructions -> machine [each time the program is run])
•C is a high level language
• One line in c maps to many lines of assembly code

Programming on Windows
DOS command line: GNU-C
• Text based editors: Notepad++
• MS-DOS/Window command line script
IDE
• Code::Blocks
http://www.codeblocks.org/
• Eclipse
https://eclipse.org/cdt/

My First C Program in
DOS Command Line
Compilation
LECTURE 2

My first C program!
/* thou shalt begin from somewhere*/
#include <stdio.h>
// program prints hello world
int main() {
printf ("Hello world!n");
return 0;
}

Files, directories and
permissions
Directory
drwxr-xr-x 2 echou cse 4096 2008-08-13 22:46 Pictures
File
-rw-r--r-- 1 echou cse 3446 2008-08-14 15:16 test.c
Special files (advanced)
• .a : static library
• .so : shared object code (dynamic)
• .o : object code
• Pipes : fifo / buffered prwx--x--x
• Device files : /dev/cdrom etc.

Programming on Windows
Writing programs
◦ Use any editor (graphical, console)
◦ Save file as <filename>.c
Compiling programs
◦ gcc <filename>.c gcc myfirst.c –o myfirst
Running programs
◦ ./a.out ./myfirst
(executable files need to have executable permissions.
$chmod +x <executable>) // for linux

Demo Program: myfirst.c
Go DOS Command!!!

My first C Program in
DOS Command Line
Compilation
LECTURE 3

Good
Programming
Practices
Variables names
• Not too short, not too long
• Always start variable names with small letters
• On work break
• Capitalize: myVariable, OR
• Separate: my_variable, OR
• Lower Case: myvariable

Rules for naming a variable
in C
•Only letters, digits and underscore_
•Start with letters or underscore only “[a-zA-Z_]”
•Case-sensitive
•No reserved words, no keywords, no known library
file name or variable names.
•There is no rule on how long a variable can be.
However, only the first 31 characters of a variable
are checked by the compiler. So, the first 31 letters
of two variables in a program should be different.
C is a strongly typed language. What this means it
that, the type of a variable cannot be changed.

Good Programming
Practices
Put comments
#include <stdio.h>
int main() {
/* this program adds
two numbers */
int a = 4; //first number
int b = 5; //second number
int res = 0; //result
res = a + b;
printf("%d + %d = %dn", a, b, res);
return 0;
}

A Simple C Program with Comments
/* Comment Block */
// comment line
•begin with /* and end with */ indicating that these two lines are a
comment.
•You insert comments to document programs and improve program
readability.
•Comments do not cause the computer to perform any action when
the program is run.

Good
Programming
Practices
•Your code may be used by somebody else
•The code may be long
•Should be easy to understand for you and for
others
•Saves lot of errors and makes debugging easier
•Speeds up program development
•Put code of a certain functionality (module) in a
file.

Code::Blocks Project
Building
LECTURE 4

Code::Blocks
Project Building
Build Build a Project
Create Create a New File
Program Program Arguments
Build Build Options
Project Project Properties
Create Create a new project (Empty Project)

Demo: Create myfirst in Code::Blocks
Go Code::Blocks!!!

Chapter 1: Introduction

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Chapter 1: Introduction