The basic concepts of Data Structure.
Computer is a machine that manipulates information. The study of Computer Science therefore, inevitably, includes the study of how information is organized in a Computer, how it can be manipulated and how it can be utilized. Thus, it is exceedingly important to understand the concept of information organization and manipulation. Computer Science can be defined as the study of the data, its representation and transformation by a digital computer.
A computer is referred to as a data processing machine using which raw data is processed to get it transformed into refined data, and this transformation is done through algorithms. Therefore we can say that raw data is input algorithms are used to transform it into refined data. The way in which the data can be processed depends on the structures that are used for representation of data. The algorithms we can use to process the data depends on the structure used for the representation of data. Therefore it becomes necessary to study the various structures for the representation of data and the algorithms that operate on these structures. Knowing the structures, one can think of the various alternative representations of the data and the corresponding operations operating on them, and choose the one that is better suited to the requirement.
Ina computer program the smallest unit of the data item that can be addressed is a memory variable and sometimes, though rarely, registers. Further, whether it is memory variable or a register, they all store data in binary form. As a result, it you take a snapshot of variables and registers at any point of time wheat you would get is a binary value. The same binary may represent a number, or a character or an address (of another variable) or even an instruction. The meaning of the stored binary value (i.e., semantic) depends on the data type of the variable. Therefore, every programming language provides a set of basic data type such as integer, character etc.
From a real world perspective, very often we have to deal with structured data items which are related to each other. For instance, let us consider the address of an employee. We can take address to be one variable of character type of structured into various fields.
As shown above Address 1 is unstructured address data. In this form you cannot access individual items from it. You can at best refer to the entire address at one time. While in the second form, i.e., Address 2, you can access and manipulate individual fields of the address – House No. Street, PIN etc. Given here under are two instance of the address 1 and address 2 variables.
Let A1, A2 be two address 1 type variables and B1, B2 be two address2 type variables. The data can now be stored in the following way.
One can access different fields of A2 as shown below:
A2: House No =446
A2: Sector =18
A2: City =CHD
A2: State = UT
A2: PIN =160018
Data structure is a combination of one of or more basic data types to form a single addressable data type along with operations define on it. Note that it is a data type and hence one can create variables of that type in a computer program. Just as each basic data type allows programmers to perform certain operations, data structures also let programmers operate on them.