Object oriented programming refers to a method of programming in which individual objects, usually called "methods" and "functions", are created and used in junction with each other to perform a function. These objects are organized within the program through use of things called structures or classes.

A class is something we use to create a blueprint of sorts for a assortment of variables and components. Similarly, a structure serves the same purpose. The only difference between a structure and a class is that a structure's members are public by default and a classes members are private by default.

Another form of "blueprint" used by programmers is the data union. While a union is very primitive in comparison to a structure or class, it is a good tool to use to conserve memory in larger applications. A union uses the same memory block for multiple variables at different points. While two variables in a union cannot be accessed at the same time, a union is a good way to re-use blocks of memory that would normally be left void after a variable is finished with.

Now that I have covered the basic points of classes, structures and unions, I will go into more detail of just how powerful a class or structure can be. In basic reference, a class is simply a blueprint to something we create instances of later in the program. This is a very vague statement however, because in object-oriented programming the class is the backbone of the program. It is what makes the program do what it is intended to do.

Members of a class are private by default, though they can be made selectively public by adding the "public:" notation before any members that are to be public. A public member of a class, typically a variable, is accessible from outside the class. A private variable is not accessible from outside the class and can only be modified or used from within the class. Below are examples of public and private variables and how they are used:

One may take notice the only difference between the class PublicVariables and PrivateVariables is that PublicVariables contains the "public:" notation before the variable declarations. This makes the variables contained within public, but what does that mean? Well, if we were to desire to change or access the variables in class PrivateVariables, we would have to create public methods and functions within the class to do so. Because a class is private by default, any variables or methods we desire to be public have to be notated as such. Because a structure is public by default, the opposite applies.

Both structures and classes can also inherit methods and attributes from other classes. Inheritance is an important tool in object-oriented programming. It allows us to use methods and attributes from other classes in new classes without having to re-write hundreds or thousands of lines of code. The importance of having inheritance available grows exponentially as programs become larger and classes grow in size. Below is an example of a class "Bravo" inheriting properties from class "Base".

In this example, class Bravo extends class Base, or in other words "inherits" the variables C, D and E from the Base class. The function "int function()" in class Bravo is able to return the value of "int C" from class Base because it is inherited to class Bravo from Base.

Finally, an important aspect of object oriented programming languages is polymorphism. polymorphism refers to objects or operators that act differently in different syntax. A simple example of polymorphism is the addition sign, "+". This operator will work in a slightly different way depending on the syntax used. For instance, if two integers are on either side of the "+" operator it will be used as mathematical addition. Below is an example with two lines of code using the "+" operator:

In this example, we have three integers, A, B, and C, and a string, D. In the first line of code after the variable declaration, the + operator is used as basic addition of integers by adding A and B and setting it to C's value. In the second line of code after the variable declaration, the + operator takes a different role. In the code "D = D + "word", the + operator is used to combine two strings. It will take "word" and add it to the end of the string "D". The + operator taking on two different roles is a perfect yet basic example of polymorphism.

Object-oriented programming languages offer many powerful capabilities. From the memory-conserving capabilities of Unions to the functionality and inheritance abilities of Classes and Structures, object-oriented programming languages such as C++ have given us the ability to take programming to the next level. Polymorphism has simplified the process and added even more functionality to an already extensive list of capabilities.