BASIC INFORMATION OF C PROGRAMMING

                    

BASIC INFORMATION OF C PROGRAMMING

            

C programming language

developed at AT and T’s bell 

laboratories in new jersey.

It was designed and written by

 "Dennis Richie " 

C is a structure programming 

language in which program is 

divided into various modules . 

each module can be written 

separately and together it forms

 a single program this structure

it easy for testing maintaining 

and debugging process. It is 

allow programming level 

language close to machine 

language it is widely used in the

 software development field ,if 

has the full support of various 

operating system and hardware

 platforms. 

                        In computer 

programming machine code, 

consisting of machine 

language instructions is low 

level programming 

language used to directly 

control a computers central 

processing unit (CPU) each 

instruction causes the CPU

to perform a very specific task 

,such as a load , store, a jump or

 an arithmetic logic unit (ALU)

operation on one or more units 

of data in the CPU`s registers 

or memory .programming 

language contains all the 

features of these language and

 many more additional concept

 that make it unique from other

 language C is powerful 

programming language which is

strongly associated with the 

Unix operating system even 

most of the Unix operating 

system is coded in c initially c

 programming was limited to 

the Unix operating  system , but

 as it started spreading around  

the world it became commercial

 ,and many compilers were 

released  for cross platform .

to sure that C language will remain 

standard , american national standards

 institute (ANSI) defined a commercial standard for c 

language in 1989 . later, it was approved by 

the international standards organization (ISO) in 1990. c programming language is also called as ANSI C.C forms a base for many other languages that are currently in use.

C is what is called a compiled 

language this means that once

 you write your c program, you 

must run it through a c compiler

 to turn your program an 

executable that the computer 

can run. 

            the program is the 

human readable form while 

the executable that comes out 

of the compiler is the compiler 

is machine readable and 

executable form what this 

means is that to write and run c

 program you must have access

to a c compiler.

why learn c?

as we studied earlier C is a base language for many programming languages . so ,learning c as the main language will play an important role while studying other programming languages . it shares the same concepts such as data types ,operators, it a simple language and provides faster execution.       

c contains 32 keywords ,various data types and a set of powerful built in functions that make programming very efficient.  

huge advantage of c is portability . different processors have different instruction sets. having to rewrite and maintain assembly language code for each computer architecture you wish to execute your code on is an onerous task . and so one of the main strengths of c is that it combines universality and portability across various computer architectures while still giving you the same kind  of low level hardware control you get with assembly language . this means you can write your c source code once and easily compile it into binaries for use on a wide variety of machines

Structure of c Program.

Comments line

Pre processor statements :

Function proto types:

Global declarations:

Main()

{

           Local declarations :

           Executable statement;

}

User defined  function()

  {         Local declarations :

            Executable statement;

}

 Types of constants

                     I.        Integers constants

                   II.        Floating point constants

                  III.        Character constants

                 IV.        String constants

C language has two types of I/O statements

Formatted I/O Statements

Printf ( ) :P

       Printf (“control string”,arguments_list);

Scanf( ):scanf is formatted input function. Scanf( )function is

 used to read information from the standard input device.

 General syntax

           Scanf (“control string”,arguments_list);

Unformatted I/O statements

getchar( ):it reads single character from standard input 

device this function don’t require any arguments .

Syntax

     Char variable name =getchar( );

Putchar( ): this function is used to display one character at 

a time on the standard output device.

Syntax

     Putchar(char_variable );

gets ( ):this function is used to read group of characters 

from the standard input device.

Syntax

    Gets (character array variable );

Puts( ): this function is used to display string to the standard

 output device.

Syntax

Puts(character array variable );

getch( ): this function reads a single character directly from 

the keyboard without displaying on the screen . this function

 is used at the end of the program for displaying the output

Syntax  

Char variable _name=getch( );

getche( ): this function reads a single character from the 

keyboard and echoes it to the current text window.

Syntax

Char variable _name =getche( );

Putch( ): this function display any alphanumeric characters

 to the standard output device .it displays only one character at a time .

Syntax

    Putch(variable_name );