DSA(Lec-1,2,3) For C++ Introduction for basics

Data Structures and
Algorithm
LECTURE 01/02 (INRODUCTION)

Course objective
Introduce methods for organizing data so that the data can be accessed
and updated efficiently within a computer program.

Course/ Lab Marking
 Assignments 10%
 Quizzes 05%
 Project 05%
 OHT Exam 30%
 Final Exam 50%

Data Structure Anyway?
It’s an agreement about:
 how to store a collection of objects in memory,
 what operations we can perform on that data,
 the algorithms for those operations, and
 how time and space efficient those algorithms are.

Data Structure Example Applications
 How does Google quickly ﬁnd web pages that contain a search term?
 How does your Operating System track which memory (disk or RAM) is
free?
 How does the processor handles multitasking

What is an algorithm?
 Well-defined computational procedure
 Takes set of values as input and produces set of values as output
 Tool to solve well defined computational problems

Data Structures and Algorithms
 Data structures
 Representation and organization of data
 Algorithms
 Methods for implementing operations on data structures
 Data structures and algorithms are closely related
 Data structures are often tuned for certain algorithms

What kind of problems are solved by
algorithms?
 Human Genome Project
 Internet: Routing, searches, security
 Electronic commerce
 Commercial enterprises
 Inflectional disease modeling

Properties of Algorithm
 Input :- Zero or more quantities are supplied.
 Output :- At least one quantity produce.
 Definiteness :- Each instruction is clear and unambiguous.
 Correctness :- An algorithm should produce the correct output values for
each set of input values.
 Finiteness :- Should produce the desired output after a finite number of steps
for any input in the set.
 Effectiveness :- To perform each step of an algorithm exactly and in a finite
amount of time.
 Generality :- The procedure should be applicable for all problems of the
desired form.

Analysis of Algorithm
The purpose of algorithm analysis is to determine:
Time efficiency/Running Time:-Performance in terms of running times for different input
sizes and structure. Running time is dependent on the size of input as well as structure
of input.
Example : Sequential search vs. Binary search
The number of comparisons done by sequential search and binary search of x
(value being searched).

Primitive Data Structure
 Integer
 Float
 Character
 Boolean

Non-Primitive Data Structure (cot.)

Array
 Contagious memory location
 Add items
 Remove item
 Replace item
 Display item

Abstract Data Type and Data Structure
Abstract data type
 Abstract Data type (ADT) is a type (or class) for objects whose behavior is
defined by a set of value and a set of operations.
 The definition of ADT only mentions what operations are to be performed
but not how these operations will be implemented.
 It does not specify how data will be organized in memory and what
algorithms will be used for implementing the operations.
 ADTs support abstraction, encapsulation and data hiding.

Abstract Data Type and Data Structure

Have you ever used a data structure
to store your data?
 Arrays in C/C++
 Stores objects sequentially in memory
 Can access, change, insert or delete objects
 Algorithms for insert & delete will shift items as needed

CLASS
 A class is simply a collection of data and methods which can act on that data.
 Classes describe a model/concept/type and defines the possible behavior and
possible states of that (in your example, a Person can have a name, address, etc.
 A class serves only as a plan, or a template, or sketch- of a number of similar things (i.e.
objects)
 A class is a mechanism for creating user-defined data types.

Objects
 An object is an instance of a
class.
 A class and an object of that
class has the same relationship
as a data type and a variable
 All objects with the same
characteristics constitute one
class.
Objects
Professor Smith
Professor Jones
Professor Mellon
Attributes

DEFINING A CLASS IN C++
class person
{
public:
Int age ;
public:
// public class members
};
Void main(){
Person p1;
P1.age =12;
}

class circle
{
private:
float radius;
public:
circle(){radius=5.5;}
circle(float r) {set(r);}
void set(float r) //sets circle
attributes
{
If(r>0)
{radius = r;}
else
{radius=5.5;}
}
float calcArea() //calculates area
{
return 3.14*power(radius,2);
}
float getRadius()
{
Return radius;
}
};
void main()
{
circle c1; //create circles
circle c2(6);
circle c3(-3);
c1.calcArea();
cout<<c3.calcArea()<<endl;
cout<<c3.getRadius();
}

Task
Create a class “Room”. Choose appropriate data members (height, breadth
and length, your program should be able to calculate
 Area of room (length * breadth)
 Volume of room (length * breadth * height)

DSA(Lec-1,2,3) For C++ Introduction for basics

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