Introduction:
C is one of most used and liked programming language in the world.Most of the programmer like it for programming.From different perspective of programming such as-program coding,compilation,application and utilization etc.,C language is specialized compared to the other language. Even making some development C language is now converted to object oriented programming language C++.
C is such a programming language that one can be a skilled programmer by practicing it regularly.
Some Basics:
For
the novice programmer some essential topics are included in as follows
which will help to understand the programming:
Program:
An
appropriate set of instructions which can solve the definite problem and
give a desired output is called program.
Given
instructions are stored in computer memory and these can be executed
anytime.For execution of program following tasks should be done:
-A set of instruction should input to the computer memory by means of input device such as key board,pen drive etc.
-Input data should be processed by the processor for desired output.
-Output data need to display by output device like monitor,printer etc.
 |
| Fig.1: Input output system. |
Terminal:
All input-output device like-keyboard,scanner,monitor,printer,plotter etc.are called terminal.
Machine language:
Computer system only can understand machine language that means 0 and 1.Writing machine language is hard and bothersome.-Program coding is very difficult,
-Time consuming,
Though writing machine language have some difficulties but it is more efficient.
Programming language:
The limitation of machine language is removed by developing programing
language.On the other hand the efficiency of program and machine remain
excellent.Traditional English,Chinese, Malay,are not the programming
language.Creating
environment for writing program,linking associate file with main
file,debugging,translation,execution,saving,closing and opening file are
operated sequentially.
Translator:
Programming language is translated to machine language or 0 and 1
through translator.It is mainly a programming software.There are
different types of translator.
- Assembler
- Interpreter
- Compiler
Hardware and Software:
Computer parts like- mouse,keyboard,monitor,microprocessor etc. are called hardware.On
the
other hand program,programming language,operating system,translator
which are required for the operation of hardware are called software.
Types of programming language:
Programming languages can be classified into three types:
- Low level language
- Mid level language
- High level language
Low level language:
In
this type of language some mnemonics like ADD,SUB,MOV,LOAD etc. are
used instead of binary code 0 and 1.Assembly language is the example of
low level language.Assembly language is translated into machine language
through assembler.
High level language:
High level language is not based on symbol or symbolic word.It is like English language.
To
use this language it is not required to learn the internal structure of
the computer in detail.Ada Modula-2,Pascal,COBOL,FORTRAN,BASIC these
are some high level language.Interpreter or compiler is used to
translate this high level language into machine language.
Mid level language:
C/C++,FORTH,Macro-assembly
language etc. are the examples of mid level language which has the
properties of both high and low level language.
4.A general purpose language:
5.Not a typed language:
Special features of C programming:
1.A mid level language:
C is called mid level language because it support some feature of high
level language and also some of low level language.
2.A structured
language:
C language is a combination of small function or
module that’s why it is easy to test,debug,maintain and execution.
3.A
portable language:
C code is extremely portable that means all computer support
C program.As for example a C program written in Apple computer can easily
transfer to the IBM PC.
4.A general purpose language:
C is called general purpose language because it is effective
for all kind of purposes.
5.Not a typed language:
All though C has five basic built in
data type but it not a typed language like
Pascal or Ada.
Basic Structure of C program:
The
basic structure or format of C program is consists with a main function
with one or more function.There are required statements in function or
sub-routine to perform specific task.General format of C program is
shown below:
Documentation section:
Some comments line or comment statements are stated in this section,these lines has no effect on execution of the program.But these will help to know about the program name,program related information.Two forward slash (//) is used for single line commenting and /* and */ are used as starting and ending respectively for many line commenting in C.
Link section:
Some header files are linked by #include directives.Compiler treat these files as a part of main file due to link.Compiler copy necessary data from library function or built in function during compilation.Linking is must for program execution.The format of linking is #include<header file name>
Example: #include<stdio.h>
Definition section:
All symbolic constants are described by #define directives.
Example: #define pie 3.1416
Global declaration section:
Variables used in many function are called global variable.Global variables are declared in above of all function.
Main function:
A main() function is must has to be in C program.There are two part in main function,declaration part and executable part.Variables used in executable part are declared in declaration part.At least one statement is must needed in executable part.A semicolon (;) must have to use in main function after each statement.In main function all statements are written between { }.
Subprogram:
This program are usually known as user defined function.This functions are called from main function.These function can be written above or below the main function.User defined function is used to make easier and understand the program.
 |
| Fig.2:Basic structure of c program. |
Some comments line or comment statements are stated in this section,these lines has no effect on execution of the program.But these will help to know about the program name,program related information.Two forward slash (//) is used for single line commenting and /* and */ are used as starting and ending respectively for many line commenting in C.
Link section:
Some header files are linked by #include directives.Compiler treat these files as a part of main file due to link.Compiler copy necessary data from library function or built in function during compilation.Linking is must for program execution.The format of linking is #include<header file name>
Example: #include<stdio.h>
Definition section:
All symbolic constants are described by #define directives.
Example: #define pie 3.1416
Global declaration section:
Variables used in many function are called global variable.Global variables are declared in above of all function.
Main function:
A main() function is must has to be in C program.There are two part in main function,declaration part and executable part.Variables used in executable part are declared in declaration part.At least one statement is must needed in executable part.A semicolon (;) must have to use in main function after each statement.In main function all statements are written between { }.
Subprogram:
This program are usually known as user defined function.This functions are called from main function.These function can be written above or below the main function.User defined function is used to make easier and understand the program.
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