Programming in C
Chapter-1
Overview of C
By:Vani Kapoor Nijhawan
Assistant Professor, VIPS
Ms. Vani Kapoor Nijhawan, VIPS
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Importance of Subject
•
C is a Structured, machine
independent and High Level
language developed by Dennis
Ritchie at AT & T’s Bell Laboratories
of USA in 1972.
•
To be a Good Programmer one
must know fundamentals of C
programming language.
Ms. Vani Kapoor Nijhawan, VIPS
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Importance of C Language

Parts of many operating systems like Windows, UNIX, Linux is
written in C because nothing beats C in the speed of execution.
Moreover, if one is to extend the operating system to work with
new devices one needs to write device driver programs, which are
exclusively written in C.

Mobile phones and palmtops and devices like microwave oven,
washing machines and digital cameras are getting smarter by the
day. This smartness comes from a microprocessor, an operating
system and a program embedded in this devices. These programs
have to run fast but also have to work in limited amount of
memory. With these constraints, C is the language of choice while
building such operating systems and programs.

In several 3D computer games where the user navigates some
object, like say a spaceship and fires bullets the game has to react
fast to the user inputs. This is where C language scores over other
languages. Many popular gaming frameworks have been built using
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C language.
Ms. Vani Kapoor Nijhawan, VIPS
History of ‘C’
❑ Root of the modern language is
ALGOL 1960. It’s first
computer language to use a block
structure.
It gave concept of structured
programming.
❑ In 1967, Martin Richards developed
a language, BCPL (Basic Combined
Programming Language)
Ms. Vani Kapoor Nijhawan, VIPS
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History of ‘C’
❑ In 1970,by Ken Thompson created a language
called as ‘B’.
❑ In 1972,by Dennis Ritchie introduced new
language called as ‘C’ .
Ms. Vani Kapoor Nijhawan, VIPS
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History of ‘C’
1972
Traditional C
1978
K&R C
1989
1990
1999
Dennis Ritchie
Kernighan &Ritchie
C89/ANSI C ANSI Committee
ANSI/ISO C ISO Committee
C99
Standardization
Commitee
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Ms. Vani Kapoor Nijhawan, VIPS
Features Of ‘C’
❖ It is a robust language with the capabilities of assembly language and
features of high level language.
❖ It is suitable for writing system softwares and business packages also.
❖ Programs written in ‘C’ are efficient and fast.
(Because of variety of data types and powerful
operators)
❖ Highly Portable. (related to OS)
❖ Well suited for structured programming.(Blocks)
❖ Ability to extend itself. (Addition to C library)
Ms. Vani Kapoor Nijhawan, VIPS
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Program & Programming Language
Program:A program is a well defined set of instructions which when carried out by
processor for some specific input, generates a specific output.
Programming language:The manner of writing a program with some predefined rules is called a
programming language. It includes symbols and rules which are related
to their use as a part of language.
i.e. Pascal, C, C++, Python, JAVA, .NET
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Ms. Vani Kapoor Nijhawan, VIPS
Types of languages
❖
Lower level languages:-
Languages which are in machine executable form i.e. machine language,
Assembly language.
❖
Higher level languages:Languages which are programmer understanable than to machine i.e.
C++,Visual basic,Java.
Ms. Vani Kapoor Nijhawan, VIPS
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Executing a HLL program
❖
There are two ways to run programs written in any high-level
language.
❖
First way is to compile the program.
❖
The other method is to pass the program through an
interpreter.
Ms. Vani Kapoor Nijhawan, VIPS
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C Compiler: Functions
❖
❖
C compiler checks for syntax errors in the
code, if any
In case if no errors are found, it returns
success and converts ‘C source code into
object code form – which is nearer to
machine executable code.
Ms. Vani Kapoor Nijhawan, VIPS
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Linker: Role
A linker is a program that combines object
modules to form an executable program.
Ms. Vani Kapoor Nijhawan, VIPS
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C Program: Example
/* Program to print a message*/
// Message.C
#include<stdio.h> /* link section*/
void main()
/* execution of program*/
{
printf(“Welcome to the World of C ”);
}
Ms. Vani Kapoor Nijhawan, VIPS
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