We want to implement array class with the following specifications: - range checking. - array assignment. - arrays that know their size. - compare arrays using '==' and '!=' operators. In the next example we will implement a simple class for integers is called Array, it has the previous specifications, and it has the following structure:

1. Introduction.

2.

Friend Function:

Is a function that: 1. is not a member of a class. 2. has access to the class's private and protected members. 3. is considered as a normal external function that is given special access privileges. 4. is not in the class's scope. 5. is not called using the member-selection operators (. and –>) unless they are members of another class. 6. is declared by the class that is granting access. We can define a friend function anywhere in the class declaration.

In real-life, complex objects are often built from smaller, simpler objects. You are built from smaller parts: a head, a body, some legs, arms, etc ... This process of building complex objects from simpler ones is called object composition. Composition is used for objects that have/has a relationship to each other. A house has a door, has a roof, has a balcony. C++ allows us to do object composition in a very simple way by using classes as member variables in other classes.

Contents:

1. Constant Variables.

2. Constant Member Functions.

Constant Variables:

Making variables constant ensures their values are not accidentally changed. Just like the built-in data types (int, double, char, etc…), class objects can be made const by using the const keyword.

Contents:

1. Destructor.

2. When Constructors and Destructors are Called.

Destructor

Is a member function in the class, which has the following characteristics: 1. It has the same name as the class preceded with a tilde '~'. For example, the destructor for class Time is declared: ~Time() 2. It doesn't return any type. 3. It is called when objects are destroyed to release all allocated resources. 4.

Contents:

1. Constructors. 2. Default Constructors. 3. Constructors with Arguments. 4. Time Class with Constructors.

Constructors:

Constructor is a member function in the class, which has the following characteristics: 1. It has the same name as the class. 2. It doesn't return any type. 3. It is called every time an instance of a class is created. 3.

Content:

1. Function overloading in C++. 2. Default arguments in c++.

Function Overloading in C++:

We can have multiple definitions for the same function name in the same scope. The definition of the function must differ from each other by the types and/or the number of arguments in the argument list. We can not overload function declarations that differ only by return type. Example: We can define a function called display to print a integer number.

Contents:

1.The Concept of Abstraction. 2.procedural Abstraction and Data Abstraction. 3.Structure in C++. 4.OOP in C++. 5.Time Class Example.