Navyug Group of College - Virpar
Unit-11 Introduction of C Language
Introduction of Computer Language
As we know, to communicate with a person, we need a specific language,
similarly to communicate with computers, programmers also need a language is
called Programming Language
Language.
What is Programming Language?
A programming language is computer language that is used by programmers
(developers) to communicate with computers.
A programming language is a set of instruction and syntax used to create software
programs.
Computer languages can
n be classified into two categories:
1) Low Level Language
2) High Level Language
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1) Low Level Language
Low level languages are the machine codes in which the instructions
are given in machine language in the form of 0 and 1 to a computer
system.
There are various programs and applications written in low level
languages that are directly executable without any interpretation or
translation.
Programs written in low-level language can be run very fast.
Low level language is also divided into two parts are :
1. Machine Language
The first generation language developed for communicating with a
Computer.
It is written in machine code which represents 0 and 1 binary digits
inside the computer string which makes it easy to understand and
perform the operations.
As we know a Computer system can recognize electric signals so here
0 stands for turning off electric pulse and 1 stands for turning on
electric pulse.
It is very easy to understand by the Computer and also increases the
processing speed.
2. Assembly Language
The second generation programming language that has almost
similar structure and set of commands as Machine language.
In assembly language, we use words or names in English forms and
also symbols.
The programs that have been written using words, names and
symbols in assembly language are converted to machine language
using an Assembler.
Because a Computer only understands machine code languages
that’s why we need an Assembler that can convert the Assembly
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level language to Machine language so the Computer gets the
instruction and responds quickly.
2) High Level Language
The assembly language was easier to use compared with machine
language as it relieved the programmer from a burden of
remembering the operation – codes and addresses of memory
location.
The languages developed which were nearer to the English language,
for the use of writing the programmer in 1960 were known as High
Level languages.
The different high level languages which can be used by the common
user are FORTRAN, COBOL, BASIC, PASCAL, PL-1, LISP, ADA, SNOBOL,
C, C++, JAVA, Python, PHP and many others.
Introduction of Programming Concept
A computer can only do what a program can make it to do. To perform a
particular task the programmer writes a sequence of instructions, called
“Program”.
An instruction is command given to the computer to perform a certain
specified operation on given data.
A set of programs written for a computer is called “Software”.
A computer contains a central processing unit (CPU) which interprets each
instruction in a program serially; sets up an internal route for flow of data,
manipulates data and stores it in the main memory. Thereafter, it fetches
the next instruction. This process continues, till the last instruction has
been executed.
Basically, processor is designed to understand a specified set of instructions
stored in the main memory in the form of binary numbers. Usually, the
number and type of instructions for different types of Micro-processor are
not the same.
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Each natural language has systematic method of using the symbols of that
language. In English, the method is given by the rule of grammar. These
rules tell us which word to use when and how to use it. Similarly, the
symbols of a particular computer language must also be used as per the set
of rules which are known as the “Syntax rule” of the language.
In case of a natural language, people can use poor or incorrect vocabulary
and grammar, and still make themselves understood. However, computers
being machines can accept only exact vocabulary, governed by strict syntax
rules of the language being used. Thus, in case of a computer language
must need to follow the syntax of language.
Introduction of C Language (History & Overview)
The base of father of programming language is ‘ALGOL’.
It was first introduced in 1960.
‘ALGOL’ was used on a large basis in European countries.
‘ALGOL’ introduced the concept of structured programming to the
developer community.
In 1967, a new programming language was announced called as ‘BCPL’
which stands for Basic Combined Programming Language.
BCPL was designed and developed by Martin Richards, especially for writing
system software. This was the era of programming languages.
Just after three years, in 1970 a new programming language called ‘B’ was
introduced by Ken Thompson that contained multiple features of ‘BCPL’.
This programming language was created using UNIX operating system at AT
& T and Bell Laboratories. Both BCPL and B were system programming
languages.
In 1972, a great computer scientist Dennis Ritchie created a new
programming language called ‘C’ at the Bell Laboratories.
It was created from ‘ALGOL’, ‘BCPL’ and ‘B’ programming language. ‘C’
programming language contains all the features of these languages and
many more additional concepts that make it unique from other languages.
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‘C’ is a 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 word, it became commercial
and many compilers were released for cross-platform systems.
Today ‘C’ runs under a variety of operating systems and hardware
platforms. As it started evolving many different versions of the language
were released.
At times it became difficult for the developers to keep up with the latest
version as the systems were running under the older versions.
To assure 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’.
Languages such as C++/Java are developed from ‘C’. These languages are
widely used in various technologies. Thus ‘C’ forms a base for many other
languages that are currently in use.
Various stages in evolution of C is as follow:
Year Language Developed By
1960 ALGOL International Committee
1963 CPL Cambridge University
1967 BCPL Martin Richards
1970 B Ken Thompson
1972 C Dennis Ritchie
C Language Overview
C language combines the power of a low-level language and high level
language.
The low-level languages are used for system programming, while high-level
languages are used for application programming.
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