What is Data Structure ?

 1.Data may be organized in different ways: the

logical or mathematical model for a particular

organization of data is called the data structure.

OR


2. A data structure is a particular way of organizing

data in a computer so that it can used efficiently.

Algorithm?

Algorithm is a clearly specified set of simple

instructions to be followed to solve a problem.

 Once an algorithm is given for a problem and decided

(somehow) to be correct, an important step is to

determine how much in the way of resources, such as

time or space, the algorithm will require.

 An algorithm that solves a problem but requires a year

is hardly of any use. Likewise, an algorithm that

requires thousands of gigabytes of main memory is

not (currently) useful on most machines.

 Efficiency?

. A solution is said to be efficient if it solves the

problem within its resource constraints. A resource

can be CPU, space or time.

. Cost: The cost of a solution is the amount of

resources that the solution consumes.

Primitive and Non-primitive Data Types?

.The primitive data types are the basic data types

that are available in most of the programming

languages. The primitive data types are used to

represent single values.

.The data types that are derived from primary data

types are known as non-Primitive data types. These

data types are used to store group of values.

Linear and Non-linear Data Structure?

. A data structure is said to be linear if its elements

form a sequence or a linear list. In linear data

structures, the data is arranged in a linear fashion

through the way they are stored in memory may not

be sequential.

. A data structure is said to be non-linear if the data is

not arranged in a sequence. The insertion and

deletion of data is there not possible in a linear

fashion.

Selecting a Data Structure?

Select a data structure as follows:


1. Analyze the problem to determine the resource

constraints a solution must meet. For example, the

available disk space.

2. Determine the basic operations that must be

supported. Quantify the resource constraints for

each operation.

3. Select the data structure that best meets these

requirements.

Data Structure Philosophy?

. Each data structure has costs and benefits.

. Rarely is one data structure better than another in

all situations.

. A data structure requires:

 space for each data item it stores,

 time to perform each basic operation,

 programming effort.