This source code is written in C++ and it is a simple code. The template functions are actually a bit easier to use than template classes, as the compiler can often deduce the desired type from the function's argument list.

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.