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Proper Guide Book in C Programming Language (You can be a Programmer)

Proper Guide Book in C Programming Language You can be a Programmer

DM. Mehedi Hasan Abid 3/18/17 Binary Pathshala

Name: DM. Mehedi Hasan Abid
Email:dmabid2050@gmail.com
CEO at Binary Pathshala
Learn Today Lead Tomorrow.
You can be a Programmer.

Abstract

Hi! My name is DM. Mehedi Hasan Abid, I am student of Daffodil International University. I have make a proper guide of C Programming Language. There are more than 100 examples and 100+ question in this book, this is the speciality of the book.If anyone practice all the example and solve all the question in the question which I have given in the last. He can be a good programmer. At last best wishes to everyone and happy coding.

C Programming Language

History

C is a powerful general-purpose programming language. It is fast, portable and available in all platforms. If you are new to programming, C is a good choice to start your programming journey. This is a comprehensive guide on how to get started in C programming language, why you should learn it and how you can learn it.

Then let’s lean about the history of C Programming Language.C was developed at Bell Laboratories in 1972 by Dennis Richie. Many of its principles and ideas were taken from the earlier language B and B's earlier ancestors B CPL and CPL. CPL (Combined Programming Language) was developed with the purpose of creating a language that was capable of both high level, machine independent programming and would still allow the programmer to control the behavior of individual bits of information. The one major drawback of CPL was that it was too large for use in many applications. In 1967, B CPL (Basic CPL) was created as a scaled down version of CPL while still retaining its basic features. In 1970, Ken Thompson, while working at Bell Labs, took this process further by developing the B language. B was a scaled down version of BCPL written specifically for use in systems programming. Finally in 1972, a co-worker of Ken Thompson, Dennis Ritchie, returned some of the generality found in BCPL to the B language in the process of developing the language we now know as C.

In 1983, the American National Standards Institute (ANSI) formed a committee to establish a standard definition of C which became known as ANSI Standard C. Today C is in widespread use with a rich standard library of functions.

What will you gain if you learn C?

If you don’t know C, you don’t know what you are doing as a programmer. Sure, your application works fine and all.

1.       You will understand how a computer works.

If you know C, you will not only know how your program works but, you will be able to create a mental model on how a computer works (including memory management and allocation). You will learn to appreciate the freedom that C provides unlike Python and Java.

Understanding C allows you to write programs that you never thought were possible before (or at the very least, you will have a broader understanding of computer architecture and programming as a whole).

2.       C is the lingua franca of programming.

Almost all high-level programming languages like Java, Python, and JavaScript etc. can interface with C programming. Also, it’s a good language to express common ideas in programming. Doesn’t matter if the person you are talking with doesn’t know C, you can still convey your idea in a way they can understand.

3.       Opportunity to work on open source projects that impact millions of people.

At first, you may overlook the fact that C is an important language. If you need to develop a mobile app, you need Java (for Android), Swift and Objective C (for iOS). And there are dozens of languages like C#, PHP, ASP.net, Ruby, Python for building web application. Then, where is C programming?

Python is used for making wide range for applications. And, C is used for making Python. If you want to contribute to Python, you need to know C programming to work on Python interpreter that impacts millions of Python programmers. This is just one example. A large number of software’s that you use today is powered by C.

Some of the larger open source projects where C programming is used are Linux Kernel, Python Interpreter, and SQLite Database.

Another language that’s commonly used for large open source project is C++. If you know C and C++, you can contribute to large open source projects that impacts hundreds of millions of people.

4.       You will write better programs.

To be honest, this statement may not be true all the time. However, knowing how computer works and manage memory gives your insight on how to write efficient code in other programming languages.

5.       You will find it much easier to learn other programming languages.

A lot of popular programming languages are based on C (and C++, considered superset of C programming with OOP features). If you know C, you will get a head start learning C++.

Languages like C# and Java are related to C and C++. Also, the syntax of JavaScript and PHP is similar to C.

If you know C and C++ programming, you will not have any problem switching to another language.

Compile and run C programming on your OS

To run C Programming in Windows we can use different types of software or with the compiler we can run C program from command prompt (cmd), there are different types of software’s (Code blocks, DevC++, Visual studio). The most popular software for C Programming Language is Code blocks so let’s see how to download a software called Code::Blocks. Then, write C code, save the file with .c extension and execute the code.

To make this procedure even easier, follow this step by step guide.

1. Go to the binary release download page of Code:Blocks official site.

2. Windows XP / Vista / 7 / 8.x / 10 section, click the link with mingw-setup (highlighted row) either from Sourceforge.net or Fosse Hub

3.Open the Code::Blocks Setup file and follow the instructions (Next > I agree > Next > Install); you don’t need to change anything. This installs the Code::Blocks with gnu gcc compiler, which is the best compiler to start with for beginners.

Now, open Code::Blocks and go to File > New > Empty file (Shortcut: Ctrl + Shift + N)

5.Write the C code and save the file with .c extension. To save the file, go to File > Save (Shortcut: Ctrl + S).

Important: The filename should end with a .c extension, like: hello.c, your-program-name.c 

6.To run the program, go to Build > Build and Run (Shortcut: F9). This will build the executable file and run it you will see the output like the below Image. 

If your program doesn’t run and if you see error message like the image below "can't find compiler executable in your search path (GNU GCC compiler)"

Then go to Settings > Compiler > Toolchain executables and click Auto-detect. This should solve the issue in most cases.

.

The Fun Begins from here

so let’s start

You will learn to write a “Hello, World!” program in this section.

Why “Hello, World!” program?

“Hello, World!” is a simple program that displays “Hello, World!” on the screen. Since, it’s a very simple program, it is used to illustrate the basic syntax of any programming language.

This program is often used to introduce programming language to a beginner. So, let’s get started.

#include <stdio.h>

int main()

{

    printf("Hello, World!\n");

    return 0;

}

How “Hello, World!” program works?

Include stdio.h header file in your program.

C programming is small and cannot do much by itself. You need to use libraries that are necessary to run the program. The stdio.h is a header file and C compiler knows the location of that file. To use the file, you need to include it in your program using #include preprocessor.

Why do you need stdio.h file in this program?

In this program, we have used printf() function which displays the text inside the quotation mark. Since printf() is defined in stdio.h, you need to include stdio.h.

The main() function

In C programming, the code execution begins from the start of main() function (doesn’t matter if main() isn’t located at the beginning).

The code inside the curly braces { } is the body of main() function. The main() function is mandatory in every C program.

int main() {

}

This program doesn’t do anything but, it’s a valid C program.

The printf() function

The printf() is a library function that sends formatted output to the screen (displays the string inside the quotation mark). Notice the semicolon at the end of the statement.

In our program, it displays Hello, World! on the screen.

Remember, you need to include stdio.h file in your program for this to work.

The return statement

The return statement return 0; inside the main() function ends the program. This statement isn’t mandatory. However, it’s considered good programming practice to use it.

Key notes to take away

• All C program starts from the main() function and it’s mandatory.
• You can use the required header file that’s necessary in the program. For example: To use sqrt() function to calculate square root and pow() function to find power of a number, you need to include math.h header file in your program.
• C is case-sensitive; the use of uppercase letter and lowercase letter have different meanings.
• The C program ends when the program encounters the return statement inside the main()function. However, return statement inside the main function is not mandatory.
• The statement in a C program ends with a semicolon.

C Keywords

Keywords are predefined, reserved words used in programming that have a special meaning. Keywords are part of the syntax and they cannot be used as an identifier. For example:

int money;

Here, int is a keyword that indicates 'money' is a variable of type integer. 

As C is a case sensitive language, all keywords must be written in lowercase. Here is a list of all keywords allowed in ANSI C. There are 32 keywords in C Programming Language.

Keywords in C Language
auto	double	int	struct
break	else	long	switch
case	enum	register	typedef
char	extern	return	union
continue	for	signed	void
do	if	static	while
default	goto	sizeof	volatile
const	float	short	unsigned

Now may be you are thinking what is variable? Ok then let’s see what is variable?

 Basic about Variables

In programming, a variable is a container (storage area) to hold data.

To indicate the storage area, each variable should be given a unique name (identifier). Variable names are just the symbolic representation of a memory location. For example:

int playerScore = 95;

Here, playerScore is a variable of integer type. The variable is assigned value: 95.

The value of a variable can be changed, hence the name 'variable'.

In C programming, you have to declare a variable before you can use it.

Rules for naming a variable in C

1. A variable name can have letters (both uppercase and lowercase letters), digits and underscore only.
2. The first letter of a variable should be either a letter or an underscore. However, it is discouraged to start variable name with an underscore. It is because variable name that starts with an underscore can conflict with system name and may cause error.
3. 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.

 

 

Tokens in C

A C program consists of various tokens and a token is either a keyword, an identifier, a constant, a string literal, or a symbol. For example, the following C statement consists of five tokens −

printf("Hello, World! \n");

The individual tokens are −

printf

(

"Hello, World! \n"

)

;

Semicolons

In a C program, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.

Given below are two different statements −

printf("Hello, World! \n");

return 0;

Comments

Comments are like helping text in your C program and they are ignored by the compiler. They start with /* and terminate with the characters */ as shown below −

/* my first program in C, 

This is for multiline comment*/

Single line comments is identified by // as shown below −

// my first program in C, 

This is single line comment.

You cannot have comments within comments and they do not occur within a string or character literals.

Identifiers

A C identifier is a name used to identify a variable, function, or any other user-defined item. An identifier starts with a letter A to Z, a to z, or an underscore '_' followed by zero or more letters, underscores, and digits (0 to 9).

C does not allow punctuation characters such as @, $, and % within identifiers. C is a case-sensitive programming language. Thus, Manpower and manpower are two different identifiers in C. Here are some examples of acceptable identifiers −

mohd       zara    abc   move_name  a_123

myname50   _temp   j     a23b9      retVal

C Programming Data Types

In C programming, variables or memory locations should be declared before it can be used. Similarly, a function also needs to be declared before use.

Data types simply refers to the type and size of data associated with variables and functions

Data types in C

1. Fundamental Data Types
• Integer types
• Floating type (float, double)
• Character type
2. Derived Data Types

·         Arrays

·         Pointers

·         Structures

·         Enumeration

This tutorial will focus on fundamental data types. To learn about derived data types, visit the corresponding tutorial.

Integer Types

The following table provides the details of standard integer types with their storage sizes and value ranges −

Type	Storage size	Value range
char	1 byte	-128 to 127 or 0 to 255
unsigned char	1 byte	0 to 255
signed char	1 byte	-128 to 127
int	2 or 4 bytes	-32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int	2 or 4 bytes	0 to 65,535 or 0 to 4,294,967,295
short	2 bytes	-32,768 to 32,767
unsigned short	2 bytes	0 to 65,535
long	4 bytes	-2,147,483,648 to 2,147,483,647
unsigned long	4 bytes	0 to 4,294,967,295

To get the exact size of a type or a variable on a particular platform, you can use the sizeof operator. The expressions sizeof (type) yields the storage size of the object or type in bytes. Given below is an example to get the size of int type on any machine −

#include <stdio.h>

#include <limits.h>

int main() {

   printf("Storage size for int : %d \n", sizeof(int));

   return 0;

}

When you compile and execute the above program, it produces the following result on Linux −

Storage size for int : 4

 

Floating-Point Types

The following table provide the details of standard floating-point types with storage sizes and value ranges and their precision −

Type	Storage size	Value range	Precision
float	4 byte	1.2E-38 to 3.4E+38	6 decimal places
double	8 byte	2.3E-308 to 1.7E+308	15 decimal places
long double	10 byte	3.4E-4932 to 1.1E+4932	19 decimal places

The header file float.h defines macros that allow you to use these values and other details about the binary representation of real numbers in your programs. The following example prints the storage space taken by a float type and its range values −

#include <stdio.h>

#include <float.h>

int main() {

   printf("Storage size for float : %d \n", sizeof(float));

   printf("Minimum float positive value: %E\n", FLT_MIN );

   printf("Maximum float positive value: %E\n", FLT_MAX );

   printf("Precision value: %d\n", FLT_DIG );

   return 0;

}

When you compile and execute the above program, it produces the following result on Linux (Don’t worry about what is linux it’s just another operating system like windows) −

Storage size for float: 4

Minimum float positive value: 1.175494E-38

Maximum float positive value: 3.402823E+38

Precision value: 6

Difference between float and double

The size of float (single precision float data type) is 4 bytes. And the size of double(double precision float data type) is 8 bytes. Floating point variables has a precision of 6 digits whereas the precision of double is 14 digits.

char - Character types

Keyword char is used for declaring character type variables. For example:

char test = 'h'

Here, test is a character variable. The value of test is 'h'.

The size of character variable is 1 byte.

Again Variable Definition in C

A variable definition tells the compiler where and how much storage to create for the variable. A variable definition specifies a data type and contains a list of one or more variables of that type as follows −

type variable_list;

Here, type must be a valid C data type including char, w_char, int, float, double, bool, or any user-defined object; and variable_list may consist of one or more identifier names separated by commas. Some valid declarations are shown here −

int    i, j, k;

char   c, ch;

float  f, salary;

double d;

The line int i, j, k; declares and defines the variables i, j, and k; which instruct the compiler to create variables named i, j and k of type int.

Variables can be initialized (assigned an initial value) in their declaration. The initializer consists of an equal sign followed by a constant expression as follows −

type variable_name = value;

Some examples are −

extern int d = 3, f = 5;    // declaration of d and f. 

int d = 3, f = 5;           // definition and initializing d and f. 

byte z = 22;                // definition and initializes z. 

char x = 'x';               // the variable x has the value 'x'.

For definition without an initializer: variables with static storage duration are implicitly initialized with NULL (all bytes have the value 0); the initial value of all other variables are undefined.

Variable Declaration in C

A variable declaration provides assurance to the compiler that there exists a variable with the given type and name so that the compiler can proceed for further compilation without requiring the complete detail about the variable. A variable definition has its meaning at the time of compilation only, the compiler needs actual variable definition at the time of linking the program.

A variable declaration is useful when you are using multiple files and you define your variable in one of the files which will be available at the time of linking of the program. You will use the keyword extern to declare a variable at any place. Though you can declare a variable multiple times in your C program, it can be defined only once in a file, a function, or a block of code.

Example

Try the following example, where variables have been declared at the top, but they have been defined and initialized inside the main function −

#include <stdio.h>

// Variable declaration:

extern int a, b;

extern int c;

extern float f;

int main () {

   /* variable definition: */

   int a, b;

   int c;

   float f;

   /* actual initialization */

   a = 10;

   b = 20;

   c = a + b;

   printf("value of c : %d \n", c);

   f = 70.0/3.0;

   printf("value of f : %f \n", f);

   return 0;

}

When the above code is compiled and executed, it produces the following result −

value of c : 30

value of f : 23.333334

Defining Constants

There are two simple ways in C to define constants −

·        Using #define preprocessor.

·        Using const keyword.

The #define Preprocessor

Given below is the form to use #define preprocessor to define a constant −

#define identifier value

The following example explains it in detail −

#include <stdio.h>

#define LENGTH 10  

#define WIDTH  5

#define NEWLINE '\n'

int main() {

   int area; 

 

   area = LENGTH * WIDTH;

   printf("value of area : %d", area);

   printf("%c", NEWLINE);

   return 0;

}

When the above code is compiled and executed, it produces the following result −

value of area : 50

The const Keyword

You can use const prefix to declare constants with a specific type as follows −

const type variable = value;

The following example explains it in detail −

#include <stdio.h>

int main() {

   const int  LENGTH = 10;

   const int  WIDTH = 5;

   const char NEWLINE = '\n';

   int area; 

  

   area = LENGTH * WIDTH;

   printf("value of area : %d", area);

   printf("%c", NEWLINE);

   return 0;

}

When the above code is compiled and executed, it produces the following result −

Value of area: 50

Note that it is a good programming practice to define constants in CAPITALS.

Escape Sequences/ Character Constants

Sometimes, it is necessary to use characters which cannot be typed or has special meaning in C programming. For example: newline (enter), tab, question mark etc. In order to use these characters, escape sequence is used.

For example: \n is used for newline. The backslash ( \ ) causes "escape" from the normal way the characters are interpreted by the compiler.

Escape Sequences/ Character Constants
Escape Sequences	Character
\b	Backspace
\f	Form feed
\n	Newline
\r	Return
\t	Horizontal tab
\v	Vertical tab
\\	Backslash
\'	Single quotation mark
\"	Double quotation mark
\?	Question mark
\0	Null character

String constants

String literals or constants are enclosed in double quotes "". A string contains characters that are similar to character literals: plain characters, escape sequences, and universal characters.

You can break a long line into multiple lines using string literals and separating those using white spaces.

Here are some examples of string literals. All the three forms are identical strings.

"hello, dear"

"hello, \

dear"

"hello, " "d" "ear"

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