7/27/10 ITK 179

04/10/23 ITK 179 1

Hardware SoftwareTheory1800 AD

Architecture1945 AD

What is Computer Science?

Languages1960 AD

2ITK 17904/10/23

Alan Turing (1912-1954) – The Enigma

The man who invented the computer

Image from http://ei.cs.vt.edu/~history/Turing.html

Turing Machines

Turing Award: the Nobel Prize in CS

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Said:

“Turing Machines are human that compute.”

“In logic nothing is accidental”

Ludwig Wittgenstein (1889-1951)

Image from http://www.ags.uci.edu/~bcarver/wgallery.html

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Hardware

0 1 1 0

24=16

0 1 0 01 1 0 0... ... ... ...

Software

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Hardware

Input device Output device

Central Processor Unit:

Internal Storage

Control Unit+

Arithmetic-Logic Unit(ALU)

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Software: 1. Operation systems2. Applications

XP,Unix,VAX

Words

Excel

E.I.

Hello

Java

Hello.javajavacHello.class

(class loader)

Eclipse,NetBean IDE, Sun

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IDE (Integrated Development Environment)1. A customized plain text editor2. Compiler3. Loader4. Debugging tool

JDK (Java Development Kid) = IDE+JRE

Eclipse = IDE

1. notepad2. javac hello3. java hello4. ......

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How much effort in solving a problem

Java's Features Solving Problem

Java's Features Solving Problem

This is more important and difficult;

data structures,algorithm analysis

This is a basic requirement. We need to reduce this portion

6 month from now

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ProblemsSolutions cycle

Problems

System analyst, Project leader

Algorithms

Senior Programmers

Programs in JAVA (or any high level Programming Language)

compiler

AssemblyAssembler

Machine code

linkerResults

Customers

ProgrammersSyntaxSemantics

(human)

IDE(computers)

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Procedure vs Object

To solve a program is:

To find a way to manipulate data --

• We design procedures • Procedure-Oriented Programming

Statements + functions programs

To find objects to model the problem –

• We choose data (object) • Object-Oriented Programming

Classes + Objects programs

(interfaces, methods, attributes…)

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What is “model”?

X models an ideal style of Y

X objects Y problem

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Class A class is a concept of something

Vehicle4 wheels, seat, engine, windows……

Truck…………

Sedan…………

SUV…………

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Objects: an instance of some class

Vehicle

SUV

Honda Pilot

011-JAV

instantiation

Class

Object

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Method & Attribute

Each class: Method & AttributeThe class designer should determine whatkind of methods and attribute its object should have

Method: behaviors, service, operation, and functionalities of the object.

Field (attribute): the information, status, and properties of the object.

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011-JAV

Honda Pilot

Honda PilotPlate: 011-JAV

Color: Blue

Engine size: 3.0 L

...

...

Start the engine()

Stop()

Turn (direction)

Air()

...

...

Services, methods

Attributes

UML (Unified Modeling Language) class diagram

Class name

Z.Turn(right)

Z

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Robotint street

int avenue

Direction direction

ThingBag backback

...

...

Robot(City aCity, int aStreet, int aAvenue, Direction aDir)

void move()

void turnLeft()

void pickThing()

void putThing()

...

...

Services, methods

Attributes

UML class diagram for Robot

Class name

Constructor

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Modeling what?Modeling Robots with Software Objects

- the title of 1.3 in ITK168 textbookBut this phrase does not make too much sense to me...

Should be: Modeling Robots in a City with Software Classes.

Robotint street

int avenue

Direction direction

ThingBag backback

...

...

Robot(City aCity, int aStreet, int aAvenue, Direction aDir)

void move()

void turnLeft()

void pickThing()

void putThing()

...

CityString name

int stree_No

...

...

....

....

City(...........)

....

....

....

....

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Object–Oriented Programming

• Model the structure and behavior of a system through the interaction of software objects that represent entities from the problem domain

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Task: deliver X from (1,2) to (3,1) and step away

X0

1

2

3

4

0 1 2 3 4import becker.robot.*;

public class DeliverX{

public static void main(String args[]){ // set up Initial situation City A = new A();

Thing X = new Thing(A,1,2); Robot karel = new Robot(A,0,0, Direction.East); // direct the robot

karel.move();karel.move();karel.turnRight();karel.move();karel.pickThing();

karek.move(); karel.move();karel.turnRight();karel.move(); karel.putThing();karel.move();

}}

name Karel

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A Java programimport javax.swing.JOptionPane;public class time{ public static void main(String args[]){

int x,y,z; String X,Y;

X = JOptionPane.showInputDialog("Input x"); Y = JOptionPane.showInputDialog("Input y"); x = Integer.parseInt(X); y = Integer.parseInt(Y);

z = x*y;

JOptionPane.showMessageDialog( null, x + " * " + y + " = " + z, "The product of " + x + " and " + y, JOptionPane.PLAIN_MESSAGE ); System.exit(0); }}

classes methods

package

arguments

Variable declaration

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Data Type

• Characterize data into different kinds for convenience

1. bit2. byte3. integer4. ascii5. character6. array7. string8. real9. record

+ operations Objects

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Abstraction

• A tool to manage complexity• Hide irrelevant details; focus on the features

needed to use a thing• Examples

– File deletion using icons– The brakes on a car– Television remote– What else?

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Data Type

• Specification View of a data type– Data values– Operations defined on those values

Abstract Data Type (ADT) –use of abstraction!

• Implementation View of a data type– Language-specific representation for the values– Implementation of the operations

Implementation of an ADT

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Abstract model of Priority Queues (Specification View)

Priority Queue

a black box

insert oneitem

Get the one with the highest priority

the minimum one(or equivalently, maximum)

Abstract Data Type (ADT)

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Abstract model of Priority Queues (Implementation View)

Binary Search Treeor

Binary Heap?

insert oneitem

Get the one with the highest priority

the minimum one(or equivalently, maximum)

Abstract Data Type (ADT)

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The Java Collections Framework (JCF)

UML Class Diagram

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Collection Operations

• Add an element• Remove an element• Replace an element• Retrieve an element• Determine if a collection

contains an element• Get the collection’s size

• Determine if a collection is empty

• Traverse a collection• Determine if two

collections are equal• Clone a collection• Serialize a collection

Most collections support the same operations, but may givethem different names.