OOPS & DS Virtual Lab

7/26/2019 OOPS & DS Virtual Lab

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Exp No.1 Sorting using Arrays

Introduction

Sorting AlgorithmsSorting is a fundamental task in computing. There are several sorting algorithms

developed decades ago, but new algorithms continue to appear. In this experiment, the focus is to

study a few classical sorting algorithms.

Primarily be using arrays for our algorithms as it is simple and illustrative to do so. It

will cover merge sort, insertion sort, and quick sort in this experiment.

Objective

To nderstand various sorting algorithms using arrays

AIM

To simulate various sorting algorithms using arrays.

Algorithms

Merge Sort Algorithm

The idea of merge sort is to shift the onus to the combine step. To this end, we

come up with the following design

! "ivide the n element input into two n#$ element sequences.

! Sort the n#$ element sequences recursively.

! %erge the two n#$ element sequences into a sorted n element sequence.

&. Procedure %erge'(,),*+ &. i &, - &

$. for k & to l r do

/. if (0i1 2 )0-1 then

3. *0k1 (0i14 i i &

5. else

6. *0k1 )0-14 - - &47. 8nd

!uic" Sort Algorithm

1


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*lgorithms based on the divide and conquer strategy called the quick sort that can

sort in place.

! "ivide9 "ivide the input into / parts (, 8, and ) where ( 2 8 2 ) based on a

pivot.

! :onquer9 Solve the sorting problem recursively on ( and ). *ssuming that all

the items are distinct, so that ;8; & hence already sorted.

! :ombine9 Produce the sorted (, 8, and ) in that order.

&. Procedure Parition'*, l, h+

$. pivot *0h14

/. i l < &4 3. for - p to h < & do

5. if *0-1 2 pivot

6. i i &4

7. swap *0i1 with *0-1

=. swap *0i &1 with *0h1

>. 8nd Procedure

?iven a pivot, partition the elements of the array such that the resulting array consists of9

&. @ne sub


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Best case9

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Corst :ase9

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8nter random input array of n integers to sort9

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#ES$%&

The Sorting using *rrays was executed successfully.

Exp No.' Expression Evaluation using Stac"s

Introduction

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Expression Evaluation

This experiment guides you using stacks in a practical example. Stacks are an important

data structure and find applications where essentially the data item that is stored latest is what

needs to be accessed first. 8xamples of applications of stacks in natural settings include a stack

of books on a table. Typically, as you pile books on a desk, the book that you can access instantly

is the one that you placed at the latest time. * good computing application of stacks is to use it to

evaluating arithmetical expressions. In this experiment, we will go through the entire expression

evaluation process. The attached notes and the slides describe the technical details. The

animation can help you understand the process via several examples. se these resources to

develop code for your own expression evaluator. To add a good interface, you can consider a

small web interface where in one can type an expression and ask for it to be evaluated. Think of

?oogle which can do this for most expressions.

&he Stac" (ata Structure

The stack data structure is characteriDed by its last


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Applications o) Stac"s

Expression Evaluation

@ne of the prominent applications of stacks is to expression evaluation. :onsider a table

calculator which evaluates arithmetic expressions involving addition, multiplication, subtraction,

and division. Gor example, $/ H 5 < 7 is a valid expression. The result of the above expression is

& as multiplication has precedence over addition and subtraction. To disambiguate, one also

uses parenthesis and write the same expression as $ '/H5+ < 7. Jowever, it would be quite

cumbersome to use parentheses when especially, the precedence is known. Jence, one needs to

first convert a given expression into a non


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such as a queue at a ticket reservation office, an operating system -ob queue, or a queue of aero

planes ready to take off. In all such settings, the element or the ob-ect that is first inserted is the

first one to come out of the queue also. Thus, the queue is a Girst


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#ES$%&

The 8xpression 8valuation using Stacks was simulated successfully.

OOPS & DS Virtual Lab

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