1. Overview of Programming Paradigms

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. Imperative Programming
IT 240

9. 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)

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

11. Modularity Interface and Implementation Compilation Libraries
Independent
Separate
Libraries