c programming tutorial, Study notes of C programming

Download c programming tutorial and more Study notes C programming in PDF only on Docsity!

C Programming Tutorial

i

C PROGRAMMING TUTORIAL

Simply Easy Learning by tutorialspoint.com

tutorialspoint.com

iii

Variable Declaration in C ................................ Error! Bookmark not defined.

TUTORIALS POINT

Simply Easy Learning Page 1

C Language Overview

This chapter describes the basic details about C programming language, how it emerged,

what are strengths of C and why we should use C.

T

he C programming language is a general-purpose, high-level language that was

originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was originally first implemented on the DEC PDP-11 computer in 1972.

In 1978, Brian Kernighan and Dennis Ritchie produced the first publicly available description of C, now known as the K&R standard.

The UNIX operating system, the C compiler, and essentially all UNIX applications programs have been written in C. The C has now become a widely used professional language for various reasons.

 Easy to learn

 Structured language

 It produces efficient programs.

 It can handle low-level activities.

 It can be compiled on a variety of computer platforms.

Facts about C

 C 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).

 The UNIX OS was totally written in C by 1973.

CHAPTER

TUTORIALS POINT

Simply Easy Learning Page 2

 Today, C is the most widely used and popular System Programming Language.

 Most of the state-of-the-art softwares have been implemented using C.

 Today's most ][popular Linux OS and RBDMS MySQL have been written in C.

Why to use C?

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:

 Operating Systems

 Language Compilers

 Assemblers

 Text Editors

 Print Spoolers

 Network Drivers

 Modern Programs

 Databases

 Language Interpreters

 Utilities

C Programs

A C program can vary from 3 lines to millions of lines and it should be written into one or more text files with extension ".c"; for example, hello.c. You can use "vi", "vim" or any other text editor to write your C program into a file.

This tutorial assumes that you know how to edit a text file and how to write source code using any programming language.

TUTORIALS POINT

Simply Easy Learning Page 4

Installation on UNIX/Linux

If you are using Linux or UNIX, then check whether GCC is installed on your system by entering the following command from the command line:

$ gcc - v

If you have GNU compiler installed on your machine, then it should print a message something as follows:

Using built-in specs. Target: i386-redhat-linux Configured with: ../configure --prefix=/usr ....... Thread model: posix gcc version 4.1. 2 20080704 (Red Hat 4.1. 2 - 46 )

If GCC is not installed, then you will have to install it yourself using the detailed instructions available athttp://gcc.gnu.org/install/

This tutorial has been written based on Linux and all the given examples have been compiled on Cent OS flavor of Linux system.

Installation on Mac OS

If you use Mac OS X, the easiest way to obtain GCC is to download the Xcode development environment from Apple's web site and follow the simple installation instructions. Once you have Xcode setup, you will be able to use GNU compiler for C/C++.

Xcode is currently available at developer.apple.com/technologies/tools/.

Installation on Windows

To install GCC at Windows you need to install MinGW. To install MinGW, go to the MinGW homepage, www.mingw.org, and follow the link to the MinGW download page. Download the latest version of the MinGW installation program, which should be named MinGW- .exe.

While installing MinWG, at a minimum, you must install gcc-core, gcc-g++, binutils, and the MinGW runtime, but you may wish to install more.

Add the bin subdirectory of your MinGW installation to your PATH environment variable, so that you can specify these tools on the command line by their simple names.

When the installation is complete, you will be able to run gcc, g++, ar, ranlib, dlltool, and several other GNU tools from the Windows command line.

TUTORIALS POINT

Simply Easy Learning Page 5

C Program Structure

Let’s look into Hello World example using C Programming Language.

B

efore we study basic building blocks of the C programming language, let us look a

bare minimum C program structure so that we can take it as a reference in upcoming chapters.

C Hello World Example

A C program basically consists of the following parts:

 Preprocessor Commands

 Functions

 Variables

 Statements & Expressions

 Comments

Let us look at a simple code that would print the words " Hello World ":

#include <stdio.h>

int main() { /* my first program in C */ printf("Hello, World! \n");

return 0 ; }

Let us look various parts of the above program:

CHAPTER

TUTORIALS POINT

Simply Easy Learning Page 7

C Basic Syntax

This chapter will give details about all the basic syntax about C programming language

including tokens, keywords, identifiers, etc.

Y

ou have seen a basic structure of C program, so it will be easy to understand other

basic building blocks of the C programming language.

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 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.

For example, following are two different statements:

printf("Hello, World! \n"); return 0 ;

CHAPTER

TUTORIALS POINT

Simply Easy Learning Page 8

Comments

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

/* my first program in C */

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 or 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_ myname50 _temp j a23b9 retVal

Keywords

The following list shows the reserved words in C. These reserved words may not be used as constant or variable or any other identifier names.

auto else Long switch

break enum register typedef

case extern return union

char float short unsigned

const for signed void

continue goto sizeof volatile

default if static while

do int struct _packed

double

TUTORIALS POINT

Simply Easy Learning Page 10

C Data Types

I

n the C programming language, data types refer to an extensive system used for

declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

The types in C can be classified as follows:

S.N. Types and Description

Basic Types: They are arithmetic types and consists of the two types: (a) integer types and (b) floating- point types.

Enumerated types: They are again arithmetic types and they are used to define variables that can only be assigned certain discrete integer values throughout the program.

The type void: The type specifier void indicates that no value is available.

Derived types: They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types.

The array types and structure types are referred to collectively as the aggregate types. The type of a function specifies the type of the function's return value. We will see basic types in the following section, whereas, other types will be covered in the upcoming chapters.

Integer Types

Following table gives you details about standard integer types with its 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

CHAPTER

TUTORIALS POINT

Simply Easy Learning Page 11

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,

unsigned int 2 or 4 bytes 0 to 65,535 or 0 to 4,294,967,

Short 2 bytes - 32,768 to 32,

unsigned short 2 bytes 0 to 65,

Long 4 bytes - 2,147,483,648 to 2,147,483,

unsigned long 4 bytes 0 to 4,294,967,

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. Following 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

Following table gives you details about 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. Following example will print storage space taken by a float type and its range values:

#include <stdio.h> #include <float.h>

int main()