Introduction of Data Structure

Data Structure is a systematic way to organize data in order to use it efficiently.
Preliminaries:-
Type:- A type is a collection of values
For Example,the Boolean type consist of the value true or false
                        Integer is a simple type because its values contains no sub parts.
A bank account record will typically contain several pieces of information such as name , address , account number and account balance.
      Such a record is an example of an aggregate type or composite type

Data Item:-A data item is a piece of information or a record whose value is drawn from a type.
                    A data item is said to be a member of type
Data Type:- A data type together with a collection of operation to manipulate.
   
Abstract data type (ADT):-
  An abstract data type is the realization of a data type as a software components.The interface of the ADT is defined in terms of a type and a set of operation on that type.The behavior of each operation is determined by its I/P and O/P.
   An ADT does not specify how the data type is implemented. These implementations details are hidden from the user of the ADT. and protected from outside access; a concept referred to as encapsulation. 
       A data structure is the implementation for an ADT.The term "data structure" often refers to data  stored in a computer's main memory.
  Eg: An ADT for a list of integer might specify the following operation:-

•  Insert a new integer at a particular position in the list
•  Return true is the list is empty
•  Reinitialize the list
•  Return the number of integer currently in the list
•  Delete the integer at a particular position in the list