Programming languages 1

Programming paradigms

Families of programming languages

Programming languages 2

Objected programming

• Important language concepts– Classes and objects– Methods– Encapsulation

• Private and protected– Inheritance– Polymorphism

• Some languages– Java– C++– C#– Smalltalk

Programming languages 3

Declarative programming

• Important language concepts– You say what you want, not how to do it.– An interpreter executes your “wish”

• Some languages– SQL (Structured Query Language)

• A DBMS (Database Management System) executes your SQL query.

Programming languages 4

Structured programming

• Important language concepts– Procedures and functions– Selections statements

• If…else, switch, etc.– Looping statements

• While, for, etc.

• Remarks– Opposed to unstructured programming

• Lots of goto statements– Object-oriented programming languages has many elements

borrowed from structured programming• Some languages

– Pascal– C

Programming languages 5

Functional programming

• Important language concepts– Lists

• Programs are represented as lists

– Functions– Recursion

• Some languages– LISP– SML – Haskell

Programming languages 6

Logic programming

• Important language concepts– Saying “what” instead of “how”

• The inference machine knows “how”• Non-procedural

– Programmer state “facts”– Programmer asks “questions”

• Answered by the inference machine, using the facts

• Some languages – Prolog

Programming languages 7

Programming language development

• Programming languages are developed with inspiration from other programming languages.– Java was inspired by C++ and Smalltalk– C# was inspired by C++ and Java

• Some languages are single paradigm– Meant to be used within a single paradigm

• Some languages are multi paradigm– Meant to be used with 2 (or more) paradigms

Programming languages 8

Using programming languages outside the paradigm

• Many programming languages can be used with more than a single paradigm

• Example– Java can be used for

• Object-oriented programming• Structured programming

– Using only static constructs

• Using a programming language outside its natural paradigm is awkward and error-prone– Find a programming language which suits the

paradigm you like.

Programming languages 9

References

• Wikipedia– Programming Paradigm

http://en.wikipedia.org/wiki/Programming_paradigm

• Bruce J. MacLennan Principles of Programming Languages, Holt Rinehart and Winston