04/07/06 Lecture Notes, CISC181

Classes!


We extend C++ with a new data type by adding a "class".


The basic syntax is the following:


class Complex_C
{

  public:

    // in here will go member functions
    // member functions are also called methods
  
  private:

    // in here will go data members
    // data members are also called attributes


};


Object Oriented Programming has four main features:
   * Encapsulation
   * Information Hiding
   * Inheritance
   * Polymorphism

Encapsulation: define functions and data _together_ in one syntactic unit.

Information Hiding: classes have a public and a private part
    public part is all users get to see
    private internal details are hidden from users

 Like on a car: everyone who drives understands:
     steering wheel
     brake
     gas pedal
     gear shift
     ignition
     light switch

 But not everyone understands---or even needs to understand:
     torque converter
     piston
     fuel injector
     etc.


Constructors: special member functions

  "construct" a new instance of a class.

  instances are "individuals"... specific
   variables in memory that are instances of the class

  Defining a class creates no instances..
  
  You have to "instantiate" the class to create
   an instance.

Read Chapters 6, 7, 8