MCA

1. Name : Daleep Kumar (
Program : MCA (Master of Computer Application)
Subject : Advance Data Structure
1. Define Modularity and explain its need in computer programs.
Modularity is the degree to which a system's components may be separated and recombined.
The meaning of the word, however, can vary somewhat by context: In biology, modularity is the
concept that organisms or metabolic pathways are composed of modules
Its need in computer programs
Modular programming is a software design technique that emphasizes separating the
functionality of a program into independent, interchangeable modules, such that each contains
everything necessary to execute only one aspect of the desired functionality.
A module interface expresses the elements that are provided and required by the module. The
elements defined in the interface are detectable by other modules. The implementation contains
the working code that corresponds to the elements declared in the interface. Modular
programming is closely related to structured programming and object-oriented programming, all
having the same goal of facilitating construction of large software programs and systems by
decomposition into smaller pieces, and all originating around the 1960s. While historically usage
of these terms has been inconsistent, today "modular programming" refers to high-level
decomposition of the code of an entire program into pieces, structured programming to the low-
level code use of structured control flow, and object-oriented programming to the data use
of objects, a kind of data structure. In object-oriented programming, the use of interfaces as an
architectural pattern to construct modules is known as interface-based programming
In software engineering, modularity refers to the extent to which a software/Web application
may be divided into smaller modules. Software modularity indicates that the numbers of
application modules are capable of serving a specified business domain.
Modularity is successful because developers use prewritten code, which saves resources. Overall,
modularity provides greater software development manageability. Modern business issues grow
on a continuous basis - in terms of size, complexity and demand. Enhanced software capability
requirements force developers to enhance developed systems with new functionalities. Software
engineering modularity allows typical applications to be divided into modules, as well as
integration with similar modules, which helps developers use prewritten code. Modules are
divided based on functionality, and programmers are not involved with the functionalities of
other modules. Thus, new functionalities may be easily programmed in separate modules
The benefits of using modular programming include:
• Less code has to be written.
• A single procedure can be developed for reuse, eliminating the need to retype the code
many times.
• Programs can be designed more easily because a small team deals with only a small part
of the entire code.
• Modular programming allows many programmers to collaborate on the same application.

2. • The code is stored across multiple files.
• Code is short, simple and easy to understand.
• Errors can easily be identified, as they are localized to a subroutine or function.
• The same code can be used in many applications.
• The scoping of variables can easily be controlled.
2. Define Queue and explain how we can implement the Queue.
The queue is a data structure that has one important difference from a stack. A stack is called a
LIFO list (Last-In-First-Out) in that the last element pushed onto a stack will be the first element
popped off. A queue, on the other hand, is a FIFO list (First-In-First-Out) in that the first element
inserted in the queue will be the first element removed. The easiest way to visualize a queue is to
think of a line of customers waiting to purchase theater tickets or see a bank teller. Usually the
next person to be served is the one who has been waiting the longest and late-comers are added
to the end of the line. (The British people "queue up" instead of waiting in lines.)
In computer science, queues are used in operating systems for a timeshared computer to keep
track of tasks waiting for the processor. If all tasks have the same priority, the one that receives
the processor is the one that has been waiting the longest. Queues are also used by operating
systems to keep track of the list of jobs waiting to be printed. We will describe the queue as an
abstract data type and show how to use a queue to represent a list of airline passengers waiting
to see a ticket agent. We will also implement an abstract data type for a queue. We will illustrate
how to use a process called simulation to determine the amount of time customers spend waiting
in queues. Lastly, we will introduce a variation on the queue known as a priority queue.
The implementation file
First, let us study an implementation without any particular tricks. Here is a possibility:
#include "queue.h"
#include "list.h"
#include < stdlib.h>
struct queue
{
list head;
list tail;
};
queue
queue_create(void)
{
queue q = malloc(sizeof(struct queue));
q -> head = q -> tail = NULL;
return q;
}
int

3. queue_empty(queue q)
{
return q -> head == NULL;
}
void
queue_enq(queue q, void *element)
{
if(queue_empty(q))
q -> head = q -> tail = cons(element, NULL);
else
{
q -> tail -> next = cons(element, NULL);
q -> tail = q -> tail -> next;
}
}
void *
queue_deq(queue q)
{
assert(!empty(q));
{
void *temp = q -> head -> element;
q -> head = cdr_and_free(q -> head);
return temp;
}
}
In the createoperation, we use the fact that in C, the assignment operation is an expression (and
thus has a value) in order to shorted the code by one line. The value of q -> tail = NULL is
itself NULL, which can be used as a value to assign to q -> head. A similar trick is used in
the enq operation.
The head field in the queue structure points to the first cell of the list, which corresponds to the
head of the queue (from where elements are dequeued), and thetail field points to the last cell of
the list, which corresponds to the tail of the queue (where elements are enqueued). Notice the
special case necessary when the queue is empty before an enqueue operation. After
a dequeue operation resulting in an empty queue, the tail field will point to a list cell that is no
longer allocated. This might be a problem if a garbage collector is used, as it might keep that cell
(and worse, its contents) alive even though it will never be used again. In that case, another
special case must be introduced in the dequeue operation, like this:
void *
queue_deq(queue q)
{
assert(!empty(q));
{
void *temp = q -> head -> element;

4. q -> head = cdr_and_free(q -> head);
if(empty(q))
q -> tail = NULL;
return temp;
}
3. List the Advantages and Disadvantages of Linear and linked representation of tree.
Advantages and disadvantages of linear representation
Advantages:
1. This representation is very easy to understand.
2. This is the best representation for complete and full binary tree representation.
3. Programming is very easy.
4. It is very easy to move from a child to its parents and vice versa.
Disadvantages:
1. Lot of memory area wasted.
2. Insertion and deletion of nodes needs lot of data movement.
3. Execution time high.
4. This is not suited for trees other than full and complete tree
List the advantages of linear representation and linked representation of binary tree.
In this representation, each node of a binary tree is defined as shown below
LEFT
DATA
RIGHT
DATA field contains information. LEFT field holds the address of left child node and RIGHT
field holds the address of right child node. If there are no children, the address fields hold null
value. The first node address is called pointer of the tree. Using this address only we can access
the tree.
Consider the tree given below.
The linked list representation of the above tree is
Advantages and disadvantages of linked representation
Advantages
1. A particular node can be placed at any location in the memory.
2. Insertions and deletions can be made directly without data movements.
3. It is best for any type of trees.
4. It is flexible because the system takes care of allocating and freeing of nodes.
Disadvantages
1. It is difficult to understand.
2. Additional memory is needed for storing pointers
3. Accessing a particular node is not easy.
4. Define binary tree traversal and explain any one traversal with example.

5. A. Binary tree traversal:- Binary tree traversal is defined as a process of visiting all the nodes in
the binary tree once. The visit always starts from the root node.
1. To read (print) or write data in the node. It is denoted by letter v.
2. To move to the left of that node. It is denoted by letter L.
3. To move to the right of that node. It is denoted by letter R.
a. In order traversal
b. Pre order traversal
c. Post order traversal
In order traversal (LVR)
This traversal is denoted by the letters LVR. The steps to be followed are
a. Start from the root node and move left until there is no left child. Then visit the last
node (print the data).
b. Move right and move left until there is no left child. Then visit the last node
c. If it is not possible to move right go back one node visit the node (print the data) and
do step
This traversal is called in order traversal.
Example: consider the binary tree
Steps
• Start from the root node A and move left till last node that is up to node B and print the
data B
• Move one step back and print the data A
• Then move right to node C and move left till last node that is upto print the data D
• Move one step back and print the data C
• Then move right to node E since no path to move. Print the data E
Therefore the result of the in order traversal is B A D C E.
Binary tree creation:
The following steps are used to create the binary tree.
• Define a self-referential structure to define the node.
• Allocate memory space for an empty node using the defined self-referential structure.
• Create the binary tree node using step i) and ii).
Step (i)- defining self-referential structure to define a node.
A node can be defined as a self-referential structure as shown below.
Struct node
{
datatype data;
Struct node *link;
struct node *rlink;
};
Where
Node – name of the structure

6. Data type – valid data type such as int, float etc.
The above structure has tree fields namely.
ü Data - variable to store data
ü *lchild - pointer variable to store the address of the left child.
ü *rchild - pointer variable to store the address of the right child.
The figure given below shows he logical structure of the node defined by the above structure.
Lchild
Data
rchild
Step (ii) – Allocating a free node
Allocation is a process of allocating free memory area for the defined struct node type for storing
the data value and the address of left and right child. The starting address of the allocated of left
and right child. The staring address of the allocated area is stored in a pointer variable. This can
be implemented in c language using the function given below.
4. List and explain any five types of graphs.
The graphs are very useful and fairly common data structures. They are used to describe a wide
variety of relationships between objects and in practice can be related to almost everything. As
we will see later, trees are a subset of the graphs and also lists are special cases of trees and thus
of graphs, i.e. the graphs represent a generalized structure that allows modeling of very large set
of real-world situations.
Frequent use of graphs in practice has led to extensive research in "graph theory", in which there
is a large number of known problems for graphs and for most of them there are well-known
solutions.
Type of Graphs:-
 Undirected Graphs
 Directed Graphs
 Vertex Labeled Graphs
 Cyclic Graphs
 Edge Labeled Graphs
 Weighted Graphs
 Directed Acyclic Graphs
 Disconnected Graphs
1. Undirected Graphs.
In an undirected graph, the order of the vertices in the pairs in the Edge set doesn't matter.
Thus, if we view the sample graph above we could have written the Edge set as {(4,6),(4,5),
(3,4),(3,2),(2,5)),(1,2)),(1,5)}. Undirected graphs usually are drawn with straight lines
between the vertices.
The adjacency relation is symetric in an undirected graph, so if u ~ v then it is also the case
that v ~ u.
2. Directed Graphs.
In a directed graph the order of the vertices in the pairs in the edge set matters. Thus u is
adjacent to v only if the pair (u,v) is in the Edge set. For directed graphs we usually use

7. arrows for the arcs between vertices. An arrow from u to v is drawn only if (u,v) is in the
Edge set. The directed graph below
Has the following parts.
o The underlying set for the Verticies set is capital letters.
o The Vertices set = {A,B,C,D,E}
o The Edge set = {(A,B),(B,C),(D,C),(B,D),(D,B),(E,D),(B,E)}
Note that both (B,D) and (D,B) are in the Edge set, so the arc between B and D is an arrow
in both directions.
3. Vertex labeled Graphs.
In a labeled graph, each vertex is labeled with some data in addition to the data that
identifies the vertex. Only the indentifying data is present in the pair in the Edge set. This
is silliar to the (key,satellite) data distinction for sorting.
Here we have the following parts.
a. The underlying set for the keys of the Vertices set is the integers.
b. The underlying set for the satellite data is Color.
c. The Vertices set = {(2,Blue),(4,Blue),(5,Red),(7,Green),(6,Red),(3,Yellow)}
d. The Edge set = {(2,4),(4,5),(5,7),(7,6),(6,2),(4,3),(3,7)}
4. Cyclic Graphs.
A cyclic graph is a directed graph with at least one cycle. A cycle is a path along the
directed edges from a vertex to itself. The vertex labeled graph above as several cycles.
One of them is 2 » 4 » 5 » 7 » 6 » 2
5. Edge labeled Graphs.
A Edge labeled graph is a graph where the edges are associated with labels. One can
indicate this be making the Edge set be a set of triples. Thus if (u,v,X) is in the edge set,
then there is an edge from u to v with label X
Edge labeled graphs are usually drawn with the labels drawn adjacent to the arcs
specifying the edges.

8. Here we have the following parts.
a. The underlying set for the the Vertices set is Color.
b. The underlying set for the edge labels is sets of Color.
c. The Vertices set = {Red,Green,Blue,White}
d. The Edge set = {(red,white,{white,green}) ,(white,red,{blue}) ,(white,blue,
{green,red}) ,(red,blue,{blue}) ,(green,red,{red,blue,white}) ,(blue,green,
{white,green,red})}
5. Explain
1. Fixed block storage allocation
2. Variable block storage allocation.
Fixed block storage allocation:-
First block storage allocation is the simplest case of dynamic storage allocation. This is the
straight forward method in which, all the blocks are of identical in size. The user can decide the
size of the block. The operating system keeps a pointer called AVAIL. This pointer points to
memory.
A user program communicates with the memory manager by means of two functions, first is
GETNODE (NODE) and second is RETURNNODE (ptr). GETNODE() procedure is used to avail
an free node from the AVAIL list whereas the RETURNNODE() is used to return the block of
memory, whenever a memory block is no longer required.

9. Whenever the GETNODE() is executed it checks for the availability of free node in the AVAIL list
and get a memory block from the AVAIL list.
Procedure returnnode() used to return back the used memory to the avail list, it will be added as
end of the list.
So far as the implementation of fixed block allocation is concerned, this is the simplest strategy.
But main drawback of this strategy is the wastage of space. For example, suppose each memory
block is of size 1k (1024 bytes)now for a request of a memory block, say, of size 1.1k we have to
avail 2 block (that is 2k memory space), thus wasting 0.9k memory space. Making the size of the
block too small reduces the wastage of space, however, it also reduces the overall performance of
the scheme.
Variable block Storage Allocation:-
To over come the disadvantages of fixed block storage, block of variable sizes are a used, which
is represented in figure 1.1. Here also linked lists play a vital role for the management of memory
blocks. The procedures used for allocation and deallocation of memory blocks from the variable
block storage are as follows.

10. This procedure assumes the blocks of memory are stored in ascending order of their sizes. The
node structure maintains a field to store the size of the block, namely SIZE. SIZEOF () is a method
that will return the size of the node. The above procedure initially check for the NULL status of
AVAIL list and proceeds with the search for the exact size of block which is requested and return
the same, if the pool does not have the requested size it will return the bigger size of block.
Procedure RETURNNODE() will return the used block of memory to the memory pool. While
returning useless like fixed block, it researches for the size of the existing pool where it can be
inserted. Because we assume that the free pool memory blocks are arranged in ascending the size
of the returning block and the same will be inserted into the memory pool.
6. What is the use of external storage devices? Explain any two external storage devices.
External storage Any type of storage device that is connected to and controlled by a computer
but is not integrated within it. Generally the devices are peripheral units such as disk drives or
tape transports. An external storage device may be shared by more than one computer.

11. This takes the form of a stand-alone device that is separate from the computer. External drives
are connected to the computer with a cable plugged into a suitable interface such as an USB port.
Data then passes back and forth across the interface.
Once an external drive is attached to the system, it appears as an extra drive letter in the folder
tree, for example, E drive or K drive. The user can transfer files in the usual way by using the
drag and drop method.
The main advantage of external drives is that they are portable and so data is easily moved from
one location to another. External drives also allow safe backup of internally stored data.
The main disadvantage compared to an internal drive is data transfer is slower and they also take
up space around the computer. Constant plugging in and out can also physically wear out the
port over time.
External storage takes many forms, for example:
• portable hard disks
• magnetic tape
• memory stick / flash drive
• solid state memory cards
• DVD or CDs
• PAN Drive
Explanation of two external storage devices
1. Optical Drive (CD/ DVD)
CD’s and DVD’s are ideal for storing a list of songs, movies, media or software for distribution or
for giving to a friend due to the very low cost per disk. They do not make good storage options
for backups due to their shorter lifespan, small storage space and slower read and write speeds.
Capacity CD : 650MB to 900MB
Capacity DVD : 4.7GB to 17.08GB
Advantages :

12. • Low cost per disk
Disadvantages :
• Relatively shorter life span than other storage options
• Not as reliable as other storage options like external hard disk and SSD. One damaged
disk in a backup set can make the whole backup unusuable.
2. Solid State Drive (SSD)
Solid State Drives look and function similar to traditional mechanical/ magnetic hard drives but
the similarities stop there. Internally, they are completely different. They have no moving parts
or rotating platers. They rely solely on semiconductors and electronics for data storage making it
a more reliable and robust than traditional magnetic. No moving parts also means that they use
less power than traditional hard drives and are much faster too.
With the prices of Solid State Drives coming down and is lower power usage, SSD’s are used
extensively on laptops and mobile devices. External SSD’s are also a viable option for data
backups.
Capacity : 64GB to 256GB
Connections : USB 2.0/3.0 and SATA
Advantages :
• Faster read and write performance
• More robust and reliable than traditional magnetic hard drives
• Highly portable. Can be easily taken offsite
Disadvantages :
• Still relatively expensive when compared to traditional hard drives
• Storage space is typically less than that of traditional magnetic hard drives.