Programming Paradigms

Unstructured programming

• Emphasis on the results of the program (the solution), without concern for how the solution is achieved.
• Spaghetti code; very difficult to maintain
• Only practical for very small, simple programs.

Procedural programming

• Emphasis on algorithmic abstractions; on processing data
• Procedures (aka functions, subroutines)
• Global scope (variables and functions available from anywhere in the program)

Modular programming

• Related functions and variables grouped together in separate files.
• File scope (variables and functions not available outside of that file)

Structured programming

• Conditional constructs (if - else)
• Looping constructs (for, while, do - while)
• Complex data structures
• Enforced relationships between data
• Nested functions
• Function arguments
• Local scope (variables and sub-functions not available outside of that function)
• Encapsulation (information hiding) (within a module)
• Modules are loosely coupled.
• Each block of code has a single entry point and a single exit point.
• Avoidance of goto statements

Functional programming

• A sequence of stateless function evaluations
• First-class functions
  
• Relies heavily on recursion

Abstract data types (ADT)

• A set of data items that can only be accessed by defined operations.

Object-oriented programming (OOP)

• Emphasis on the behavior and attributes of tangible or abstract entities (objects)
• Class (the behavior and attributes of a tangible or abstract entity)
• Object (an existing occurrence of a class) (aka instance)
• Interface (an abstract class that provides the behavior and attributes for a category of classes without defining the class)
• Abstraction (implementation hiding) (within a class).
• Encapsulation (information hiding) (within a class)
• Inheritance (heirarchical reuse of behavior and attributes between similar classes)
• Polymorphism (an object's behavior is based on its place in the inheritance hierarchy at run-time)

Post-object programming

Weaknesses of OOP

• Localizing concerns involving global constraints or pandemic (widespread) behaviors
• Appropriately segregating concerns
• Applying domain specific knowledge.

Possible successors to OOP

• Aspect-oriented programming (AOP)
• Domain-specific languages
• Generative programming
• Generic programming
• Constraint languages
• Reflection and metaprogramming
• Feature-oriented development
• Views/viewpoints
• Asynchronous message processing

Sources

• Design Patterns: Elements of Reusable Object-Oriented Software; Gamma, Helm, Johnson, Vlissides; 1995; Addison Wesley

• http://en.wikipedia.org
  
• http://eies.njit.edu/~haibin/Lesson1.ppt
• http://www.cecs.csulb.edu/~tayek/575/aop/aop.html
• http://america3.pcs.cnu.edu/~tdunn/cpsc231/oop.htm
• http://cs.hiram.edu/~guercioa/cs172/chap07-class-long