We Know that C++ Language Provides us the various types of data types like Int,Float Char etc These are also called the Predefined Data types those are used for Storing the values in the Variables

We know that Files are used for Storing Permanent information. And C++ provides a Facility to a developer the Retrieve the Information from File and he may also modify the Contents of a File So that we can say that File Handling is the Concept to Store, Retrieve and Modify the Information which is stored in the Form of Files in your Computer.

Arrays:- When there is a need to use many variables then There is a big problem because we will Conflict with name of variables So that in this Situation where we wants to Operate on many numbers then we can use array . The Number of Variables also increases the complexity of the Program. So that we uses Arrays.

Union is also like a Structure means Unions is also used for Storing data of different data types But the Difference b/w Structure and Union is that Structure Consume the Memory of addition of all elements of Different Data Types but a Union Consume the Memory that is Highest among all variables.

These are the Special Variables those are used storing the address of variable .We know that Every variable must be Stored in Memory of Computer or in other words a Small part of Memory if used by a Variable For Storing his value So that For Storing a Value into a variable