Introduction to Programming Paradigims

INTRODUCTION TO PROGRAMMING PARADIGIMS

1. INTRODUCTION

Usually computer software may be classified into application software and system software. Application software is the set of programs necessary to carry out operations for specific applications. System software are the general programs written for the system, which provide the environment to facilitate the writing of application software. Programming language translators are the best example of system software.

2. WHY PROGRAMMING LANGUAGES?

The purpose of using computers is to solve problems, which are difficult to solve manually. So the computer user must concentrate on the development of good algorithms for solving problems. After preparing the algorithms, the programmer has to concentrate the programming language which is understandable by the computer.

Computer programming languages are developed with the primary objectives of facilitating a large number of people to use computer without the need to know the details of internal structure of the computer.

Languages are matched to the type of operation to be performed in algorithms for various applications. Languages are also designed to be machine independent.

3. HIGH LEVEL LANGUAGES

This section describes some of the popular high level languages and the areas of their applications.

FORTRAN: It stands for FORmula TRANslation, which is the oldest high level language. This language was developed by John Backus and his team at IBM in 1956‒57. The main aim behind the development of this language is to solve scientific and engineering applications. The first version of this language was used in 1950s and early 1960s it was known as FORTRAN‒II, next popular version was FORTRAN‒IV. In 1977, the FORTRAN77 was released which was more powerful than its predecessors.

COBOL: It stands for Common Business Oriented Language. The work of this language began in 1959 in USA, department of defense under the guidance of Grace Murray Hooper, and further it is maintained by CODASYL (COnfereance ‒on DAta SYstem. Language). The first formal COBOL was published in 1960 and revised in 1965 and this version was gradually enhanced. ANSI has standardized COBOL in 1968, 1974 and in 1984. Currently COBOL is a widely used programming language for business data processing.

BASIC: It stands for Beginners All Purpose Symbolic Instruction Code, developed in Darmouth College, USA in 1963 by Dr.John G.Kemeny and Thomas E.Kurtz. It is developed for the users who are starting their learning in computers and it can be learnt quickly.

PASCAL: It is named after the French mathematician Blaise Pascal and it is designed and developed by Nickolus Wirth in 1971. The main objective behind this language development was, to allow beginners to learn good problem solving and programming methods.

'C' Language: The following chapters elaborates details about the 'C' Programming language.

4. HISTORY OF 'C' LANGUAGE

'C' is one of the most popular programming languages, it was developed by Dennis Ritchie at AT & T's Bell Laboratories at USA in 1972. It is an upgraded version of two earlier languages, called BCPL and B, which were also developed at Bell laboratories.

The root map for all modern computer languages is started through the ALGOL language, in early 1960's after then COBOL was being used for commercial applications, FORTRAN was being developed for scientific Applications. At this stage, people started thinking about the single language which can program all possible applications.

A committee was formed to develop a new language called Combined Programming Language (CPL) at Cambridge University. It seemed to abstract. too general another language called Basic Combined Programming Language (BCPL) was developed by Martin Richards at Cambridge University with some additional features than CPL.

At the same time, a language called 'B' was developed by Ken Thompson at AT & T's Bell labs. But like BCPL and B turned out to be very specific, Dennis Ritchie developed a language with some additional features of BCPL and B which is very simple, relatively good programming efficiency and a relatively good machine efficiency called 'C' language, consequently the ANSI (American National Standard Institute) has begun to work on a standardised definition of 'C' Language to make it still powerful.

The following table illustrates the history of "C" Language.

5. FEATURES AND APPLICATIONS OF 'C' LANGUAGE

i) 'C' is a general purpose, powerful, efficient, compact and flexible structured programming language.

ii) 'C' is highly portable (i.e., It can be run in different operating systems environments).

iii) 'C' is a robust language whose rich set of built in functions and operators can be used to write any complex program.

iv) 'C' has the ability to extend itself. We can continuously add our own functions to the existing library functions.

v) 'C' is well suited for writing system software as well as application software.

vi) 'C' program can be run on different operating systems of the different computers with little or no alteration.

vii) 'C' is a middle level language, i.e. it supports both the low level language and high level language features.

viii) 'C' language allows reference to a memory allocation with the help of pointers, which holds the address of the memory location.

ix) 'C' language allows dynamic memory allocation i.e. a program can request the operating system to allocate or release memory at runtime.

x) 'C' language allows manipulation of data at the lowest level. This feature is extensively useful in writing system software program.

xi) 'C' is a widely available, commercial 'C' compilers are available on most PC's.

xii) 'C' programs are fast and efficient, has got rich set of operators.

xiii) 'C' can be applied in systems programming areas like Compilers, Interpreters and Assemblers etc.