Propedéutico de Programación

(1)

Propedéutico de

Programación

Coordinación de Ciencias

Computacionales

9/13

Material preparado por:

Dra. Pilar Gómez Gil

(2)

Chapter 4

(3)

ADT Sorted List

Remember the difference between an unsorted list and a

sorted list?

Remember the definition of a key?

If the list is a sorted list

of names, what would be the key?

of bank balances, what would be the key?

of grades, what would be the key?

(4)

ADT Unsorted List Operations

•

Transformers

–

MakeEmpty

–

InsertItem

–

DeleteItem

•

Observers

–

IsFull

–

GetLength

–

RetrieveItem

•

Iterators

–

ResetList

–

GetNextItem

change state

observe state

process all

(5)

ADT Sorted List

•

Which member function specifications and

implementations must change to ensure

that any instance of the Sorted List ADT

remains sorted at all times?

–

InsertItem

–

DeleteItem

(6)

•

La inserción tendrá que ser de tal manera que

(7)

Linked Implementation

What about passing spot where item

would be if there?

(8)

•

Is Inserting as easy? Let's see

Set location to listData

Set moreToSearch to (location != NULL)

while moreToSearch

switch (item.ComparedTo(location->info))

case GREATER

:

Set location to location->next

Set moreToSearch to (location != NULL)

case LESS : Set moreToSearch to false

See

the

problem

(9)

(10)

Inserting ‘S’ into a Sorted List

‘C’ ‘L’ ‘X’

Private data:

length

3

listData

currentPos ?

predLoc location

moreToSearch

(11)

Finding proper position for ‘S’

‘C’ ‘L’ ‘X’

Private data:

length

3

listData

currentPos ?

predLoc location

NULL

moreToSearch true

(12)

Finding proper position for

‘

S

’

‘C’ ‘L’ ‘X’

Private data:

length

3

listData

currentPos ?

predLoc location

moreToSearch true

(13)

Finding Proper Position for

‘

S

’

‘C’ ‘L’ ‘X’

Private data:

length

3

listData

currentPos ?

predLoc location

moreToSearch

false

(14)

Inserting

‘

S

’

into Proper Position

‘C’ ‘L’ ‘X’

Private data:

length

4

listData

currentPos

predLoc location

moreToSearch false

‘S’

(15)

•

Ver

sorted.h

(16)

•

Does DeleteItem have to be changed?

(17)

Object-Oriented Design Methodology

•

Object-oriented design decomposes a problem into classes

•

Four stages to the decomposition process

–

Brainstorming

–

Filtering

–

Scenarios

(18)

•

Brainstorming

•

A group problem-solving technique that involves the

spontaneous contribution of ideas from all members of the

group

–

All ideas are potential good ideas

–

Think fast and furiously first, and ponder later

–

A little humor can be a powerful force

(19)

•

Filtering

•

Determine which are the core classes in the problem

solution

–

There may be two classes in the list that have many

common attributes and behaviors

–

There may be classes that really don’t belong in the

(20)

•

Scenarios

•

Sequences of steps that describe an interaction between a

client and an application or program

–

Simulate class interactions

–

Ask “What if?” questions

–

Assign responsibilities to each class

–

There are two types of responsibilities

•

What a class must know about itself (knowledge)

•

What a class must be able to do (behavior)

•

Use case

(21)

Role

playing

(22)

•

Responsibility Algorithms

•

The algorithms must be written for the

responsibilities

–

Knowledge responsibilities usually just return

the contents of one of an object’s variables

–

Action responsibilities are a little more

complicated, often involving calculations

Responsibilities algorithms are often

decomposed using top-down design

(23)

Relationships Between Classes

•

Containment

–

“part-of”

–

An address class may be part of the definition of a student

class

•

Inheritance

–

Classes can inherit data and behavior from other classes

–

“is-a”

(24)

Computer Example

•

Let’s work through this problem-solving process by

creating an address list

•

Brainstorming and filtering

–

Circling the nouns and underlining the verbs is a good way

(25)

Computer Example

•

First pass at a list of classes

list

name

telephone number

email address

list

order

names

list

scraps

paper

cards

Filtered List

(26)

CRC Cards

(27)

CRC Cards

(28)

CRC Cards

(29)

Person Class

Initialize

name.initialize()

Write "Enter phone number; press return."

Get telephone number

Write "Enter email address; press return."

Get email address

Print

name.print()

Write "Telephone number: " + telephoneNumber

Write "Email address: " + emailAddress

Tells name to initialize itself

(30)

Name Class

Initialize

"Enter the first name; press return."

Read firstName

"Enter the last name; press return."

Read lastName

Print

Print "First name: " + firstName

Print "Last name: " + lastName

r sorted.h

r sorted.cpp