C For Swimmers : Mastering C step-by-step

Introduction to Data Structures

Definition : 

The logical inter-relation between elementary data items is called as data structure. The basic data items include integers, bits, characters. 

Basically it deals with manipulation and organization of data, solving problems with computer involves data manipulation. But the data available will usually be in amorphous form. When different types of such data are related to each other, then we call it to be a data structure.
Ex : Queues, Trees, etc.

D = { d , F , A }

Where,
D : Data structure
d : Domain variable
F : A set of functions or procedures operating on domain variables.
A : A set of axioms or rules which governing the operations of these functions on the domain variable.

Advantages

The major advantages of data structures are :
• It gives different level of organizing data.
• It tells how data can be stored and accessed in its elementary level

Operation on Data Structures

The operations that can be performed on data structures are :
Creation : This operation creates a data structure. The declaration statement causes space to be created for data upon entering at execution time.

Destroy : This operation destroys the data structure and aids in the efficient use of memory.

Selection : This operation is used to access data within a data structure. The form of selection depends on the type of data structure being accessed.

Update : This operation changes or modifies the data in the data structure and it is an important property in selection operation.

Types of Data Structures

Linear Data Structure : Stacks, Queues, Linked Lists, etc.

Non-linear Data Structure : Trees, Graphs, etc.

Back to Basics

Array : Array is an ordered set which consists of a fixed number of objects. No deletion or insertion operations are performed on arrays.

List : List on the other hand is an ordered set containing of a variable number of elements to which insertions and deletions can be made. The list is divided into two types :

• Stacks and 
• Queues.

File : File is typically a large list that is stored in the external memory of a computer. Ex: Magnetic disk.