Classification of languages:
Language is an interface among the programmer and computer
hardware.
According the program development and execution efficiency
languages are classified into low-level, high-level and middle level languages.
Low-level languages:
These are the languages developed and used before 60s.
These are the machine oriented languages which are difficult
to learn and practice.
Prior knowledge in computer organization (technical
knowledge) is needed to learn these languages.
These languages have low program development efficiency and
high program execution efficiency (difficult to develop but effective in
execution).
Examples:
Machine language
Assembly language (ALP).
High-level languages:
These are the programmer friendly languages.
Simple English words, operators and expressions made the
language easy to learn and practice.
Any body from any field can learn these languages to develop
software according to their requirement.
These languages have high program development efficiency and
low program execution efficiency (Easy to develop but slow in execution).
Examples:
BASIC (Beginners All Purpose Symbolic Instruction Code).
-Used to
develop small applications.
COBOL (Common Business Oriented Language)
-Used to
develop business applications
Pascal
-Used to
develop scientific applications.
FORTRAN (Formula Translation)
Middle level languages:
According to the program development and execution
efficiency, the performance of these languages is existed in between both the
low-level and high-level languages.
Examples:
C, C++, Java etc.
Need of translator:
Natural language of computer hardware is the machine
language.
Computer can’t directly understand the source code written
any high-level and middle-level languages.
We need a translator to translate the source code into
executable code.
According to the functional nature these are of two types.
Interpreter
Compiler
Interpreter:
It is a translator, translates the source code into
executable code, statement after statement in a procedural order.
The executable code generated by the interpreter is executed
by the computer hardware.
Interpreter accepts the data from either the user or from
other source while executing the program.
Need both the source code and interpreter every time we
execute the program.
Compiler:
It is a translator; translates the total source code into
executable code at once.
The executable code generated by the compiler is used as an
application (software).
We no more require either the source code or compiler once
the, compiler produces the executable code.
Most of the languages like C, C++, and Pascal etc. use
compiler.
C-compiler:
A C-program can’t directly interact with the computer,
needs a compiler. There are different compilers available to translate the
source code into executable code. Examples: Turbo C, Borland C, ANSI C and Quick C etc.
.
History of C-Language:
Up to 60’s different low-level and high-level languages were
used develop different applications in different fields.
ALGOL-60 is the language developed by International
Community during 1960.
It is a general purpose language may be used to develop any
application in any field.
But, it is an abstract language.
CPL (combined programming language) is developed by
It is used on special purpose.
It is difficult to learn.
BCPL (Basic Combined Programming Language) is developed by
Martin Richards at
It is a general purpose language.
It is easy to learn.
B is the simplified version of BCPL developed by Ken Thomson
at AT&T’s
It is developed for DEC-PDP 7 to deal with specific purpose.
C is the development version of B-Language.
It is a general
purpose language developed by Dennis Ritchie at AT&T’s
It is the language of UNIX. Most of the UNIX and its software’s
are developed in C-Language.
Though C is developed on DEC-PDP 11 under UNIX operating
system, it can be used on many operating systems including MS-DOS.
In 1983 ANSI established a committee whose goal was to
produce “an unambiguous and machine independent definition”.
C got ANSI standards during 1989. It has also adapted the
standards of ISO. The first version of ANSI/ISO C is released during 1990.
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