C language Programming: Simple, Short, and Straightforward Way of Learning C Programming
Copyright 2016 - KDP Edition
Sherwyn Allibang
Edition License
Notes
This book is authorized
for your own personal use. This book may not be re-sold or offered away to
other individuals. Much thanks to you for regarding the diligent work of the
author.
Introduction
This book is for absolute beginners
with or without prior knowledge in programming, as this book uses Simple words, Short sentences, and Straightforward
paragraphs. The triple S way of
learning C language programming. The topics covered in this book includes brief
introduction to C language, variables, data types, control structures,
functions, pointers, and input and output stream to external files. This book
starts its discussion from short history to installation of the needed software
resource and a step by step screen shots of how to write C language code,
compile and execute C programs. It presents graphical representation of
algorithms for simpler learning. This book is packed with working and running C
program samples and after reading this book, the reader would be able to develop
and create C language programs based particularly from problems given in
computer science courses, hence, adopting to other programming language will be
a lot easier. This book is your first
step in your programming career.
TO GOD BE ALL THE GLORY!
The resources used in
this book are:
> Personal Computer running
Windows 7 Operating System
> Dev-C++ available at http://bloodshed.net
Other Windows OS versions can also
be used as long as it supports the above mentioned software. Also, you may ought
to use other C compilers or IDE.
NOTE: All links provided in this book are updated occasionally. If a link becomes unavailable, email
me at zherwyndbest@facebook.com
This chapter presents a brief
overview of C language. It presents the things needed in starting C language
programming.
Short
history of C Language
C is a general-purpose high level
language that was originally developed by Dennis Ritchie for the Unix operating
system. It was first implemented on the Digital Equipment Corporation PDP-11
computer in 1972. The Unix operating
system and virtually all Unix applications are written in the C language. C has
now become a widely used professional language for various reasons:
1. Easy to learn.
2. Structured language.
3. Produces efficient programs.
4. It can handle low-level
activities.
5. It can be compiled on a variety
of computers.
6. It has a low-level language
capability with the convenience of high-level programming.
C language was invented to write
an operating system called UNIX. C is a successor of B language which was
introduced around 1970. The language was formalized in 1988 by the American
National Standard Institute (ANSI). By 1973 UNIX OS almost totally written in
C. Today C is the most widely used System Programming Language. Most of the
state of the art software have been implemented using C language.
Reasons
to use C Language
To start with, I highly recommend
C language for any beginning programmers to start their programming career
because most of the high-level and other popular programming languages today is
based from C language. Once you've learned the concepts behind programming
language with C, adopting or migrating to other language will be easy as most
of the things needed are pretty similar.
C was initially used for system
development work, in particular the programs that make-up the operating system.
C was adopted as a system development language because it produces code that runs
nearly as fast as code written in assembly language. Some examples of the use
of C might be:
1. Operating Systems
2. Language Compilers
3. Assemblers
4. Text Editors
4. Print Spoolers
5. Network Drivers
6. Modern Programs
7. Data Bases
8. Language Interpreters
9. Utilities
10. C Program File
Beginning
to Program in C Language
All the C programs are written
into text files with extension ".c" for example "hello.c", where
".c" is extension file name. These text files are called source
files. The source files contains the C source codes and will later be
transformed into a running executable file. The program development cycle of C
language are:
1. Write the source codes into a
text editor (ex: notepad) to create the source file.
2. Compile the source file to
create the object file.
3. The object file is link into an
executable (ex: .exe for windows) file.
4. Run the program and see the
result.
Based from the program development
cycle of C, notice that there are several things needed which includes a text
editor, a compiler, and a linker. The good news is that, there is a software
that comprises the three. It is called Dev-C++ which is available at http://bloodshed.net and for the download
direct link at http://bloodshed-dev-c.en.softonic.com/download.
Dev-C++ is a C source code editor,
a compiler, and a linker. All the things needed in creating a C program.
Note: You may ought to use other C compilers.
Installing
the Dev-C++
Download the installer at the link
provided above and install. Figure 1.1 presents the first screen upon running the
installer.
Definition
of programming terms
The following terms are defined
conceptually and operationally in order to have a common understanding of the
terms used in this book.
Argument. Arguments are actual value being pass to a function.
Bug. A bug is a general term used to describe any unexpected
problem with the program during execution or when the programming is already
running.
Block. A block is composed of two or more C statements. Also called
compound statements. A block is enclosed with a pair of { } braces.
CamelCase. CamelCase is the naming convention for compound word
which uses capital letters to delimit the word parts. For example, "studName",
"studAge", and "intNum".
Clause. A section in the statement.
Code. It is the term used for statements written that make up a C
program.
Condition. A statement that evaluates to either true (non zero) or
false (zero).
Data Type. It the type of data being stored to a storage location
like variable.
Debug. This refers to the process of examining and removing errors
from a program's source code.
Expression. It is a statement that result to a numeric value.
Function. Function perform a specific task.
Label. Label is used a give details to a certain line of code in C
language, hence this labels are ignored by the compiler, thus it does not
affect the output of the program. Usually used for internal documentation.
Null. In computer programming, null is the term used for an
uninitialized, undefined, empty, or meaningless value.
Parameter. Parameters are argument declaration of a function.
Statement. A statement is a complete direction instructing the
computer to carry out some task. In C, statements are usually written one per
line, although some statements span multiple lines. This term can be
interchangeably use with code.
Syntax. Syntax is the grammar, structure, or order of the elements
in a C language or any other programming language statement. (Semantics is the
meaning of these elements.)
Variable. Variables are storage location for data in C programs.
The
components of a C program
Lets discuss the components of a C
programs through a sample program. This program prints the word "Hello
World!" into the screen.
Code listings of figure 2.1
#include"stdio.h"
main()
{
/*The line below prints a string*/
printf("Hello
World!");
getch();
}
Line 1. #include"stdio.h"
This line includes a C library for
the use of the program. The inclusion of library in C program usually comes
first.
Syntax #include directive:
#include"<lib-name>"
The <lib-name> in the syntax
should be replaced with the library name. The other term for library is
"include file" because literally, a library is a separate disk file
that contains information needed by the program or the compiler.
The #include
directive instructs the C compiler to add the contents of library or include
file (sometimes called "Header files") into the program during
compilation. The library files usually comes with the compiler, hence in
Dev-C++, several libraries comes together with its default installation. These
library files should have a ".h" file extension.
In line 1, the library included is
the "stdio.h" which stands for standard
input/output. This library is used in dealing with programs that accepts
input and provides output, hence this is the most used library. Other libraries
are discussed in the succeeding chapters of this book.
Line 2. main()
This line defines the main body of
the program. The only component that is required in every C program is the main()
function. In its simplest form, the main() function consists of the
name main
followed by a pair of empty parentheses ( ) and a pair of braces { }
presented in lines 3 and 7. Within the braces are statements that make up the main
body of the program. Under normal circumstances, program execution starts at
the first statement in the main() function and terminates at
the last statement in main().
Lines 3 and 7. { }
The curly braces { } are used to
enclose the program lines that make up every C function including the main()
function. A group of one or more statements enclosed within braces is called a
block. Line 3 signifies the start of the content of the main function and line
7 signifies its end.
Line 4. /*The line below prints a string*/
The /* */ (slash asterisk asterisk slash), are called
comments. Anything enclose within the /* and */ becomes a comment. Comments are
text details usually used by programmers to reference a line code statement in
the source file. The comments are ignored by the compiler, hence does not
affect the output of the program. The program will execute and run properly
with or without comments. In line 4, the comments are used to give a reference
or details that the next line will print a string on-screen.
Syntax for single-line comment:
/* <string-comment> */
The <string-comment> in the
syntax should be replaced with a text entries that represents the comment of
the programmer in the code. The comment can be on a single line or multi-line.
Line 4 is an example of single line comment. Other compilers allows // as single
line comment, which anything that follows // in the same line is considered
comment. DevC++ allows the use of // as a single line comment.
Syntax for multi-line comment:
/*
<string-comment-string-comment
-string-comment> */
Line 5. printf("Hello World!");
The printf() statement is a
library function under "stdio.h" library that displays information
on-screen. The printf() statement can display a simple text message or the
value of one or more program variables.
Syntax of printf() in printing
literal text:
printf("<string-to-print>");
In the syntax, anything inside the
" " double quotes is considered a literal text and will be printed
on-screen. The <string-to-print> should be replaced with the
text entries to be printed on-screen. The printf function must end with a ;
semi-colon.
Line 5. getch();
The getch() "get
character", is library function that accepts a character from the
keyboard. The entered character however is not displayed on-screen. If the getch()
is omitted from the code, the program will run, but upon printing the word
"Hello World!", the program will immediately terminate. The program
output closes immediately and may not be seen by the user. Hence the getch()
is used as the trigger that when the output is presented on-screen, the user
will have to press a key in the keyboard before the program terminates. The getch()
is used as a terminator for the rest of the sample programs in this book. The getch()
function must end with a ; semi-colon.
Note: The getch() and getche() functions are
not a standard C functions as they are part of the conio library, but most C
compilers supports this function including Dev-C++ and Turbo C. If you are
using other compiler (especially for Linux OS) and the program does not run,
you may ought to use getchar() instead of getch().
Writing,
compiling, and running our first program
In writing the source file, open
the Dev-C++ and create a new source file as presented in figure 2.2.
Enjoyed the sample? You may download the complete book at AMAZON.COM
Topics covered are:
Short history of C Language
Reasons to use C Language
Beginning to Program in C Language
Installing the Dev-C++
Self-assessment questions
Definition of programming terms
The components of a C program
Writing, compiling, and running
our first program
Correcting errors
Statements
Null Statements
White spaces
Self-assessment questions
Variable
Variable Declaration and
definition
Scope of variables
Constants
Keywords
Conversion specifiers of data
types
Self-assessment questions
Displaying text on-screen
puts() function
printf() function
Literal text
An escape sequence
Accepting user input
getch() function
getche() and getchar() functions
scanf() function
gets() function
Self-assessment questions
What is an Array?
Single-Dimensional
Multi-Dimensional Array
Strings
Declaring and defining a string
Defining a string using input
functions
Strings' pre-defined functions
Length of a String
Concatenation of Strings
Compare Two Strings
Copy Strings
Reversing the Order of a String
Converting Uppercase Strings to
Lowercase Strings
Converting Lowercase Strings to
Uppercase Strings
Self-assessment questions
Expressions
Operators
Assignment Operator
Mathematical Operators
Binary
Unary
Mathematical operators precedence
level and parentheses
Relational Operators
Logical Operators
Type Casting
Pre-defined Mathematical Functions
acos()
asin()
atan()
atan2()
cos()
cosh()
sin()
sinh()
tan()
tanh()
exp()
log()
log10()
pow()
sqrt()
ceil()
fabs()
floor()
fmod()
Self-assessment questions
The if() statement
Single-alternative
Dual-alternative
Multiple-alternative
Nested if() statement
The switch() statement
Things to consider in conditional
statement
Self-assessment questions
What is a Loop?
Counter-controlled loop
for() loop statement
Nested for() loop statement
Condition-controlled loop
Pre-test loop
Post-test loop
The Infinite Loop
Self-assessment questions
User-defined function
User-defined function prototype
User-defined function definition
Calling a user-defined function
Things to consider in functions:
Self-assessment questions
Structures
Declaring a structure
Defining a structure
Accessing Structure Members
Compound declaration and
definition of structure
Self-assessment questions
Pointers in C language
Pointer Declaration and definition
How pointers works?
Pointer Arithmetic
Self-assessment questions
File management in C
Defining and opening a file
Closing a File
Reading and writing a file
putc() and getc() functions
fprintf() and fscanf() functions
Deleting a File
Renaming a File
Self-assessment questions
