Programming languages1 Programming paradigms Families of programming languages

Programming languages2 Objected programming Important language concepts –Classes and objects –Methods –Encapsulation Private and protected –Inheritance –Polymorphism Some languages –Java –C++ –C# –Smalltalk

Programming languages3 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 languages4 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 languages5 Functional programming Important language concepts –Lists Programs are represented as lists –Functions –Recursion Some languages –LISP –SML –Haskell

Programming languages6 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 languages7 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 languages8 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 languages9 References Wikipedia –Programming Paradigm adigm adigm Bruce J. MacLennan Principles of Programming Languages, Holt Rinehart and Winston