programming paradigms chapter 1

8/6/2019 Programming Paradigms Chapter 1

1/17

CSC305 (PROGRAMMING PARADIGMS)

Lecture 1 : Introduction To Programming Paradigms

1SEMESTER JAN APR 09


2/17

REASONS TO STUDY CONCEPTS OF

PROGRAMMING LANGUAGES

1. Increase the ability to express ideas

2. Improve background for choosingthe appropriate languages

3. Increase the ability to learn newlanguages

4. Better understanding on the

significance of softwareimplementation

5. Overall advancement of computing

2SEMESTER JAN APR 09


3/17


4/17

HISTORY OF PROGRAMMING

LANGUAGES

SEMESTER JAN APR 09 4

The Abacus

The Pascaline

AutomaticCalculator

Jacquard Loom

The Difference

Engine


5/17

HISTORY OF PROGRAMMING

LANGUAGES


Years Details

1842 Ada Augusta Bryon

the first computer programmer

innovations1. subroutine2. looping

1937 The Universal Machine

Alan Turing

1940s The ENIAC (1942)

The Von Neumann Concepts1. shared-program techniques2. conditional control transfer

Konrad Zuse & Plankalkul first algorithmic programming language defined circa 1945 but never implemented

Plankalkul

algorithms in the language include a program to play chess

finally published in 1976

include some advanced data types such as floating point, arrays &records


6/17

THE FIRST PROGRAMMING

LANGUAGES (1950s)


Languages &

Years

Details

Pseudocodes

(1949) the first high level programming language

1. Short Code : John Mauchly (1949)

expression were coded left to right

hand compiled

2. Speed Coding : John Backus (1953 / 54) conditional & unconditional branching

interpreter left only 700 words for user program

3. Laning & Zieler System (1953)

subscripted variables, function calls & expression

translation

FORTRAN(1954 - 57)

FORmula TRANslator developed at IBM under the guidance of John Backus

primarily for scientific, computational programming

dramatically changed forever the ways computers are used

has continued to evolved

among the most efficient compilers for producing Fastcode


7/17


LANGUAGES (1950s)


Languages& Years

Details

COBOL(1959)

Common Business Oriented Language the first business oriented language based on FLOW-MATIC

names up to 12 characters, with embeddedhyphens English names for arithmetic operators data & code were completely separated

contributions:

1. first micro facility in a high level language2. hierarchical data structures (records)3. nested selection statements4. long names (up to 30 characters) with

hyphens5. data division


8/17


LANGUAGES (1950s)


Languages &

Years

Details

LISP

(1959)

List Processing language

designed at MIT by John McCarthy

AI research needed a language that:

1. process data in l ists

2. symbolic computation

one universal recursive data type : s-expression syntax is based on Lambda Calculus pioneered functional programming

no need for variables or assignment control via recursion & conditional expressions

programs-as-data

garbage collection

Algol 58

semicolon as a statement separator assignment operator was :=

if had an else if clause

compound statement (begin .. end)

concept of type formalized

names could be of any length

arrays could have any number of subscripts

parameters were separated by mode (in & out)


9/17


LANGUAGES (1950s)


Languages& Years

Details

Algol 60 block structure (local scope) 2 parameter passing methods subprogram recursion stack dynamic arrays no I/O & no string handling successes:

1. standard way to publish algorithms forover 20 years

2. all subsequent imperative languages arebased on it

3. first machine independent language4. first language with formally defined syntax

(BNF)5. never widely used


10/17

AN EXPLOSION IN PROGRAMMING

LANGUAGES (1960s)


Languages& Years

Details

PL / I(1963 / 64)

good for scientific & business applications

eventually grew to include virtually idea in current practicalprogramming languages translator were slow, huge & unreliable

contributions:1. first unit level concurrency2. first exception handling3. switch selectable recursion4. first pointer data type

BASIC(1964)

Beginners All purpose Symbolic Instruction Code

designed by Kemeny & Kurtz at Dartmouth

goals:

1. easy to learn & use for non science students & as a path toFORTRAN and Algol

2. pleasant & friendly3. fast turnaround for homework4. free & private access5. user time is more important than computer time6. well suited for implementation on first PCs


11/17

SIMPLICITY, ABSTRACTION,

STUDY (70s)


Languages

& Years

Details

C aim for simplicity by reducing restrictions of the type system

allows access to underlying system

interface with OS - UNIX

Pascal designed by Niklaus Wirth designed for teaching structured programming

small & simple

introduces some modest improvements, such as the case

statement

was widely used for teaching programming (1980 - 1995)

C(1972)

designed for systems programming at Bell Labs by Dennis Richie& colleagues

powerful set of operators, but poor type checking

initially spread through UNIX & the availability of high quality,

free compilers

memory model is close to underlying hardware

flexible


12/17


13/17

CONSOLIDATION & NEW

PARADIGMS (1980s)


Languages &Years

Details

Ada(1979)

primarily known as DoD-1

contributions:1. packages support for data abstraction2. exception handling3. generic program units4. concurrency

LogicProgramming

based on formal logic

operational basis: solving queries relative to theory represented byprogram1972: PROLOG (PROgramming in LOGic)

unification goal seeking with backtracking

FunctionalProgramming

Common Lisp : consolidation of LISP dialects spurred practical use

Scheme : a simple & pure LISP like language used for teachingprogramming Logo : used for teaching young children how to program

Haskell : polymorphicaly typed, lazy, purely functional language


14/17

CONSOLIDATION & NEW

PARADIGMS (1980s)


Languages &Years

Details

ML Meta Language

strongly typed functional language

first developed by Robin Miller intended for interactive use

combination of LISP & Algol like features:1. expression oriented2. higher order functions3. garbage collection4. abstract data types5. module system6. exceptions

Simula 67 first OO language designated for simulation

later recognized as general purpose programming language extension of Algol 60

standardized as Simula in 1977

inspiration to many later designers


15/17


16/17

THE INTERNET (1990s)


Languages

& Years

Details

Perl

(1987) Practical Extraction and Reporting Language

interpreted scripting language

original application : system administration & data

reduction data manipulation

rapid application development block structured, also supports OO

associative arrays instead of records or structures

Java(early 1990s)

developed by James Gosling & others at SunMicrosystems original goal : a language for embedded computers

original name : Oak started as reimplementation of C++

has references, no pointers

includes support for Applets & concurrency


17/17

PROGRAMMING DOMAINS


Programming Domains Purpose

FORTRAN Scientific applications

COBOL Business applications

LISP, Prolog Artificial intelligence

PL/S, BLISS, Extended Algol, C System programming

sh, awk, Perl Scripting languages

LISP, COGO, APT Special purpose languages

programming paradigms chapter 1

Documents