Overview of Programming Paradigms

Definitions Programming Paradigm Programming Language programming “technique” (?) way of thinking about programming view of a program Programming Language consists of words, symbols, and rules for writing a program

Programming Paradigms Imperative Programming program as a collection of statements and procedures affecting data (variables) Object-Oriented Programming program as a collection of classes for interacting objects Functional Programming program as a collection of (math) functions

Some Languages by Paradigm Imperative (also called Structured or Procedural) Programming FORTRAN, BASIC, COBOL, Pascal, C Object-Oriented Programming SmallTalk, C++, Java Functional Programming LISP, ML, Haskell

History of Languages 1950s to 1960s 1960s to 1970s 1970s to 1980s FORTRAN, COBOL, LISP, BASIC 1960s to 1970s (ALGOL-based) Pascal and others 1970s to 1980s Prolog, C, Ada 1980s to 1990s C++, ML, Perl, Java

Paradigm Change For example, from Structured to Object-Oriented Arises from problems encountered in one paradigm but addressed in another Case study: from C to C++ Evolution from structured, to modular, to object-based, to object-oriented programming

Object-Oriented Programming Incorporates both encapsulation and inheritance through the class concept Focus is on writing good classes and on code reuse Examples Shape, Circle, and Rectangle in a drawing program Employee, Faculty, Staff in a university personnel system

Imperative Programming IT 240

Imperative Programming Variables, assignment, sequencing, iteration, procedures as units State-based, assignment-oriented Global variables, side effects Program units: Data (Variables) and Computation (Statements and Routines)

Data and Computation Binding Data Computation Variables Data types Assignments and expressions Control structures Subprograms / routines

Modularity Interface and Implementation Compilation Libraries Independent Separate Libraries