Slide 1

Data Types

Object Interactions

Tracing

Introduction toObject-Oriented

Programming

Lesson 2:Classes and Instances

Slide 2

Review

Slide 3

Components are objects.The programmer determines the attributes and methods

needed, and then creates a class.A class is a collection of programming statements that define

the required objectA class as a “blueprint” that objects may be created from.An object is the realization (instantiation) of a class in

memory.

Classes can be used to instantiate as many objects as are needed.

Each object that is created from a class is called an instance of the class.

A program is simply a collection of objects that interact with each other to accomplish a goal.

Classes and Objects

Slide 4

Class Think: generic concept

The concept of a circle

The concept of a car

The concept of a giraffe

Instance (aka Object) Think: physical object

The green circle with a 4 cm diameter on my shirt

My blue Nissan minivan with the dent on the side

Stella, the female giraffe who lives at the Philadelphia zoo

Key Concept: Class vs. Instance

Slide 5

DATAaka “attributes”aka “state”

For example: Circle data:

Diameter, color, (x,y) location, visibility …

Car data: Make, model, year, color …

Giraffe data: Height, weight, birthday, name …

ACTIONSaka “methods”aka “functions”

For example: Circle methods: moveDown(), changeSize(), makeVisible() …

Car methods: startEngine(), reverse(), setColor() …

Giraffe methods: eat(), walk(), sleep(),setWeight() …

Classes specify types of data object store

and types of actions the objects can do

Object

Attributes (data)

Methods(behaviors / procedures)

Slide 6

Objects have operations which can be invoked (Java calls them methods).

Methods may have parameters to pass additional information needed to execute.

Objects First with Java - A Practical Introduction using BlueJ, © David J. Barnes, Michael Kölling

Methods and parameters5-6

Slide 7

Many instances can be created from a single class.

An instance has attributes: values stored in fields.

The class defines what fields an instance has, but each instance stores its own set of values (the state of the instance).

Objects First with Java - A Practical Introduction using BlueJ, © David J. Barnes, Michael Kölling

Other observations8

Slide 8Objects First with Java - A Practical Introduction using BlueJ, © David J. Barnes, Michael Kölling

State8-9

Slide 9Objects First with Java - A Practical Introduction using BlueJ, © David J. Barnes, Michael Kölling

Two circle objects10

Slide 10

public class HelloWorld{ public static void main(String[] args) { String message = "Hello World"; System.out.println(message); }}

Programming LanguagesSample Program

Key words in the sample program are:

Key words are lower case (Java is a case sensitive language). Key words cannot be used as a programmer-defined identifier. Semi-colons are statement terminators and are used to end Java

statements; however, not all lines of a Java program end a statement.

Part of learning Java is to learn where to properly use the punctuation.

• public• class

• static• void

Curly braces mark off a

block of code

Slide 11

There are differences between lines and statements when discussing source code.

System.out.println(

message);This is one Java statement written using two lines. Do you

see the difference?

A statement is a complete Java instruction that causes the computer to perform an action.

Programming LanguagesLines vs Statements

Slide 12

Getting picky with terminology

Slide 13

Class versus Object versus Instance Class is a “template” / “blueprint” that is used to create objects

Objects have two main characteristics – state and behavior. An object stores its state in fields and exposes its behavior through methods.

An instance is a unique copy of a Class. When a new instance of a class is created, the JVM will allocate a room of memory for that class instance.

Technically both classes and instances are objects. An instance is an instantiated object derived from a class

mySquare = new Square();

Any Class in Java is actually derived from a class called Object (like objects such as arrays)

Many elements of Java are objects.

Terminology Check

Slide 14

Instance Variable vs. Field vs. Property vs. Attribute (almost synonymous)

These terms are loosely used as synonyms.

A Field  or Instance Variable is generally a private variable on a instance class. It does not mean there is a getter and setter.

Property is a field that you can get or set, typically with a getter or setter

Attribute is a vague term. It refers to anything that describes an object.

Made more confusing in that different languages sometimes use these terms a little differently.

Terminology Check

Slide 15

Objects have operations which can be invoked Java calls them methods

Sometimes they are called functions or procedures

Methods allow changing or accessing properties/characteristics of the object

Methods may have parameters to pass additional information needed to execute. I may also refer to parameters as arguments

You can tell what parameters a method takes by looking at its signature. I may also refer to signatures as prototypes

Terminology: Methods

15

Slide 16

But slides have much

greater detail

Data types

7

Slide 17

Data in a Java program is stored in memory.Variable names represent a location in memory.Variables in Java are sometimes called fields.Variables are created by the programmer who

assigns it a programmer-defined identifier.ex: int hours = 40;

In this example, the variable hours is created as an integer (more on this later) and assigned the value of 40.

Programming LanguagesVariables

Slide 18

Primitive data types

are built into the

Java language and

are not derived

from classes

Murach’s Java Programming, C3 © 2011, Mike Murach & Associates, Inc.

The Eight Primitive Data Types

Type Bytes Use

byte 1 Very short integers from -128 to 127.

short 2 Short integers from -32,768 to 32,767.

int 4 Integers from -2,147,483,648 to 2,147,483,647.

long 8 Long integers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

float 4 Single-precision, floating-point numbers from - 3.4E38 to 3.4E38 with up to 7 significant digits.

double 8 Double-precision, floating-point numbers from - 1.7E308 to 1.7E308 with up to 16 significant digits.

char 2 A single Unicode character that’s stored in two bytes.

boolean 1 A true or false value.

Slide 19

Variable Declarations take the following form: DataType VariableName;

byte inches;

short month;

int speed;

long timeStamp;

float salesCommission;

double distance;

Variable Initialization occurs when the variable is set to its first value

Variable Declarations and Initialization

Slide 20Murach’s Java Programming, C3 © 2011, Mike Murach & Associates, Inc.

Initialization and Declaration of Variables

type variableName; variableName = value;

Example int counter; // declaration statement counter = 1; // assignment statement

type variableName = value;

Examples int counter = 1; // initialize an int variable double price = 14.95; // initialize a double variable float interestRate = 8.125F; // F indicates a floating-point value long numberOfBytes = 20000L; // L indicates a long integer int population = 1734323; // initialize an int variable int population = 1_734_323; // underscores improve readability double distance = 3.65e+9; // scientific notation char letter = 'A'; // stored as a two-digit Unicode char char letter = 65; // integer value for a Unicode character boolean valid = false; // where false is a keyword int x = 0, y = 0; // initialize 2 variables w/ 1 statement

SYNTAX: How to declare and initialize a variable in two statements

SYNTAX: How to declare and initialize a variable in one statement

Slide 21

byte, short, int, and long are all integer data types.They can hold whole numbers such as 5, 10, 23, 89, etc. Integer data types cannot hold numbers that have a decimal

point in them. Integers embedded into Java source code are called integer

literals.Examples of integer values:

24, -46, 0, etc.

Integer Data Types

Slide 22

Example: Integer Data Types

// This program has variables of several of the integer types.public class IntegerVariables{ public static void main(String[] args) { int checking; // Declare an int variable named checking. byte miles; // Declare a byte variable named miles. short minutes; // Declare a short variable named minutes. long days; // Declare a long variable named days.

checking = -20; miles = 105; minutes = 120; days = 185000; System.out.print("We have made a journey of " + miles); System.out.println(" miles."); System.out.println("It took us " + minutes + " minutes."); System.out.println("Our account balance is $" + checking); System.out.print("About " + days + " days ago Columbus "); System.out.println("stood on this spot."); }}

Slide 23

Data types that allow fractional values are called floating-point numbers. 1.7 and -45.316 are floating-point numbers.

In Java there are two data types that can represent floating-point numbers. float - also called single precision

(7 decimal points)

double - also called double precision (15 decimal points)

Real numbers: 43.56, 3.7e10, -3.0, -7.192e-19

Real Number Data Types

Slide 24

When floating-point numbers are embedded into Java source code they are called real number literals.

The default data type for floating-point literals is double.

29.75, 1.76, and 31.51 are double data types.

Java is a strongly-typed language. Every variable must have a data type

A double value is not compatible with a float variable because of its size and precision. float number;

number = 23.5; // Error!

A double can be forced into a float by appending the letter F or f to the literal. float number;

number = 23.5F; // This will work.

Real Number Literals (1)

Slide 25

Literals cannot contain embedded currency symbols or commas.grossPay = $1,257.00; // ERROR!grossPay = 1257.00; // Correct.

Real number literals can be represented in scientific notation.47,281.97 == 4.728197 x 104.

Java uses E notation to represent values in scientific notation.4.728197X104 == 4.728197E4.

Floating Point Literals (2)

Slide 26

// This program demonstrates the double data type.

public class Sale{ public static void main(String[] args) { double price, tax, total;

price = 29.75; tax = 1.76; total = 31.51; System.out.println("The price of the item " + "is " + price); System.out.println("The tax is " + tax); System.out.println("The total is " + total); }}

Example: Double Data Type

Slide 27

Decimal Notation

Scientific Notation

E Notation

247.91 2.4791 x 102

2.4791E2

0.00072 7.2 x 10-4 7.2E-4

2,900,000 2.9 x 106 2.9E6

Scientific and E Notationfor Doubles

// This program uses E notation.

public class SunFacts{ public static void main(String[] args) { double distance, mass;

distance = 1.495979E11; mass = 1.989E30; System.out.print("The Sun is " + distance); System.out.println(" meters away."); System.out.print("The Sun's mass is " + mass); System.out.println(" kilograms."); }}

Slide 28

The Java boolean data type can have two possible values. true

false

The value of a boolean variable may only be copied into a boolean variable.

The boolean Data Type

// A program for demonstrating// boolean variables

public class TrueFalse{ public static void main(String[] args) { boolean bool;

bool = true; System.out.println(bool); bool = false; System.out.println(bool); }}

Slide 29

The Java char data type provides access to single characters.

char literals are enclosed in single quote marks. 'a', 'Z', '\n', '1‘, '\u00F6' (ö)

Don’t confuse char literals with string literals. char literals are enclosed

in single quotes.

String literals are enclosed in double quotes.

The char Data Type

// This program demonstrates the// char data type.

public class Letters{ public static void main(String[] args) { char letter;

letter = 'A'; System.out.println(letter); letter = 'B'; System.out.println(letter); }}

Slide 30

Internally, characters are stored as numbers.

Character data in Java is stored as Unicode characters.

The Unicode character set can consist of 65536 (216) individual characters.

This means that each character takes up 2 bytes in memory.

The first 256 characters in the Unicode character set are compatible with the ASCII* character set.

*American Standard Code for Information Interchange

Unicode

// This program demonstrates the// close relationship between// characters and integers.

public class Letters2{ public static void main(String[] args) { char letter;

letter = 65; System.out.println(letter); letter = 66; System.out.println(letter); }}

Slide 31

Unicode

A

0065

B

0066

0 0 0 0 0 0 0 0 0 1 0 0 0 0 10 0 0 0 0 0 0 0 0 0 1 0 0 0 0 01

Slide 32

Unicode

A

0065

B

0066

0 0 0 0 0 0 0 0 0 1 0 0 0 0 10 0 0 0 0 0 0 0 0 0 1 0 0 0 0 01

Characters arestored in memory

as binary numbers.

Slide 33

Unicode

A

0065

B

0066

0 0 0 0 0 0 0 0 0 1 0 0 0 0 10 0 0 0 0 0 0 0 0 0 1 0 0 0 0 01

The binary numbersrepresent thesedecimal values.

Slide 34

Unicode

A

0065

B

0066

0 0 0 0 0 0 0 0 0 1 0 0 0 0 10 0 0 0 0 0 0 0 0 0 1 0 0 0 0 01

The decimal valuesrepresent these

characters.

Copyright © 2015 Pearson Education, Inc. Slide 35

Binary CodeBinary Number System: 1s & 0s

Bit –smallest unit of digital information

8 bits = 1 byteBinary code has two possible

states: on/off, 1/0, yes/noWith 8 bits there are 256

different possible combinations

Number of Bits(switch

es)Possibiliti

es

Power of

Two

1 2 20

2 4 21

3 8 22

4 16 23

5 32 24

6 64 25

7 128 26

8 256 27

Slide 36

The odometer model Think of odometers in old cars

or gas station pumps

Counting in base 10

How to Count

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 1

0 0 0 0 0 0 0 2

0 0 0 0 0 0 0 3

0 0 0 0 0 0 0 4

0 0 0 0 0 0 0 5

0 0 0 0 0 0 0 6

0 0 0 0 0 0 0 7

0 0 0 0 0 0 0 8

0 0 0 0 0 0 0 9

0 0 0 0 0 0 1 0

0 0 0 0 0 0 1 19 is the last digit. The wheel flips back

to 0, and the second wheel starts to turn

Slide 37

Our numbers (base 10) 10 digits: 0 through 9

Binary (base 2) 2 digits: 0 through 1 Usage: How computers store

data

Octal (base 8) 8 digits: 0 through 7 Usage: UNIX/Linux file

permissions

Hexadecimal (base 16) 16 digits: 0 through 9, A, B, C,

D, E, F Usage: Color codes

Counting in Octal

Bases

© 2006 Pearson Addison-Wesley. All rights reserved

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 1

0 0 0 0 0 0 0 2

0 0 0 0 0 0 0 3

0 0 0 0 0 0 0 4

0 0 0 0 0 0 0 5

0 0 0 0 0 0 0 6

0 0 0 0 0 0 0 7

0 0 0 0 0 0 1 0

0 0 0 0 0 0 1 1

7 is the last digit. The wheel flips backto 0, and the second wheel starts to

turn

Slide 38

Remember "places"?

Binary

Base Conversions (1)

the "one's" place (100)

the "ten's" place (101)

the "hundred's" place (102)

the "thousand's" place (103)

1 0 9 2

We have 2 ones

We have 9 tens

We have 0 hundreds

We have 1 thousand

2

90

0

1000

1092

the "one's" place (20)

the "two's" place (21)

the "four's" place (22)

the "eight's" place (23)

1 0 1 1

We have 1 ones

We have 1 two

We have 0 fours

We have 1 eight

1

2

0

8

What does the binary number 1011 translate to in base 10?

base 10

Slide 39

HEXADECIMAL

OCTAL

Base Conversions (2)

the "one's" place (80)

the "eight's" place (81)

the "sixty-four's" place (82)

the "512's" place (83)

1 4 0 2

the "one's" place (160)

the "sixteen's" place (161)

the "256's" place (162)

the "4096's" place (163)

0 0 1 D

Slide 40

public class OctalAndHex {

public static void main(String args[]) { int octalEleven = 013; // Note leading zero int hexEleven = 0xB; // Note leading 0x System.out.println("Octal: " + (octalEleven + 3)); System.out.println(" Hex: " + (hexEleven + 3)); }

}

Octal: 14 Hex: 14

Hexadecimal and Octal in Java

Slide 41

Object Interaction

Slide 42

Building a House(Answer these questions using

BlueJ)

What is a class?What is an object?What is an instance of a class?What are parameters to the method call?What are the fields in a class?What are the fields in an object?What is the state of an object? (use the

object inspector)What are the attributes in an object’s

fields?Why are parameters specified differently

for methods changeSize and changeColor?What are the data types of the various

parameters?

42

Slide 43

We had to create all the objects manually.

What are the next steps? Change color

of roof object to green

Move roof horizontally

Move roof vertically

Create new Circle called "sun" …

Making a House (Exercise 1.9)

Slide 44

The house project demo

Slide 45

ProjectCompileObject Bench

Additional BlueJ concepts

45

demo

Slide 46

Each class has source code (Java code) associated with it that defines its details (properties and methods).

Examine code of class Circle (double click)

Examine declaration of the class fields: private int diameter;

private int xPosition;

private int yPosition;

private String color;

private boolean isVisible;

Examine the class headers

Source code12

Slide 47

Object InteractionCompare fi gures project to house project

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; … public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

12

Slide 48

New class Picture

Attributes (data)

Methods (actions)

Examining a class (1)

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; … public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();Why don't we have to

change the color of wall?

12-13

Here are some of the actions we did manually

Slide 49

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; … public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

Class Header Gives a name to the class and

defines its access

Class Body The body of a class definition. The

body groups the definitions of a class's members (i.e., fields and methods)

Examining a class (2)12-13

Slide 50

"wall" is a property / attribute of Picture.

So is "window"

Each are instances of class Square.

"draw" is a method of picture.

"moveVertical" is a method of the instance "wall"

So is "makeVisible"

Note how these instance methods are called (invoked).

Parameters to the methods are enclosed in parentheses

Note that the Class Square is the "blueprint" which means that all square instances will have the same methods.

Examining a class (3)

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; … public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

12-13

Slide 51

All the methods in the house project are defined as void. This means they do not return a value; but …

… methods may return a result via a return value.

Such methods have a non-void return type.

More on this in the next chapter.

Examining a class (4)

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; … public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

14

Return value

The value returned from a method

Slide 52

/** * The Student class represents a student in a student * administration system. * It holds the student details relevant in our context. * * @author Michael Kalling and David Barnes * @version 2011.07.31 */public class Student {

...

// Return the full name of this student. public String getName() { return name; }

// Set a new name for this student. public void changeName(String replacementName) { name = replacementName; }

The lab-classes project:Return Values 14demo

return value

no return value

Slide 53

Objects you make and manipulate on the object bench disappear when You quit from BlueJ

You change the source code

Source code sticks around, as long as you save it Remember if you “save” rather than “save as”

you may overwrite the book example files!

What Sticks Around?

Slide 54

Sorry you can’t!But you can “record” the things you would

do inside a method in the source code View terminal window

Options: record method calls

Saving work you do on the object bench

Slide 55

Tracing a simple program

Slide 56

It is important that we distinguish different types of variables.

Before we start tracing…

Slide 57

Primitive variables actually contain the value that they have been assigned.

int number = 25;

The value 25 will be stored in the memory location associated with the variable number.

Objects are not stored in variables, however. Objects are referenced by variables.

Primitive vs. Reference Variables

number

25

int

memory location

Slide 58

When a variable references an object, it contains the memory address of the object’s location.

Then it is said that the variable references the object.private Square wall = new Square();

Primitive vs. Reference Variables

2-58

wall

Square

memory location

wall: Square

size

120int

xPosition

170int

yPosition

140int

color

"red"Str

isVisible

truebool

Slide 59

Instance Variable A field of a class. Each

individual object of a class has its own copy of such a field.

public class Picture { private Square wall; private Square window; private Triangle roof; private Circle sun; ...

Local Variable A variable defined inside a

method body.

public static void main (String[] args) { ... double discountPercent = .2;

Local vs. Instance Variables

Slide 60

method: main

Tracing local variables

sc

Scanner

subtotal

500

double

a Scanner object

“scrap paper”

Slide 61

Two circle objects: Book notation

Slide 62

Tracing Instance Variables

circle_1: Circle

diameter

50int

xPosition

80int

yPosition

30int

color

"blue"Str

isVisible

truebool

circle_2: Circle

diameter

30int

xPosition

230int

yPosition

75int

color

"red"Str

isVisible

truebool

I note the type of each

field

Book Notation:

Slide 64

Inspecting myPicture: BlueJ

64

Slide 65

Inspecting myPicture: BlueJ

65

Slide 66

Inspecting myPicture: BlueJ

66

Slide 67

My notationwall: Square

size

120int

xPosition

170int

yPosition

140int

color

"red"Str

isVisible

truebool

window: Square

size

40int

xPosition

190int

yPosition

160int

color

"black"Str

isVisible

truebool

roof: Triangle

height

60int

width

180int

xPosition

230int

color

"green"Str

isVisible

truebool

yPosition

80int

sun:Circle

diameter 80

int

xPosition

330int

yPosition

50int

color

"yellow"Str

isVisible

truebool

myPicture:Picture

wall

Square

window

Square

roof

Triangle

sun

Circle

Slide 68

Looking at the Picture Class

Names of all of the fi elds in the classseem to be listed at the top of the code

public class Picture{ private Square wall; private Square window; private Triangle roof; private Circle sun;

myPicture:Picture

wall

Square

window

Square

roof

Triangle

sun

Circle

Slide 69

Looking at the Picture Class

public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

Create a new instance of the Square class

called “wall”

Do the setup for “wall”

Setup for all of the fields seems to be insidethe draw method

wall: Square

size

120int

xPosition

170int

yPosition

140int

color

"red"Str

isVisible

truebool

Slide 70

Looking at the Picture Class

public void draw() { wall = new Square(); wall.moveHorizontal(-140); wall.moveVertical(20); wall.changeSize(120); wall.makeVisible(); window = new Square(); window.changeColor("black"); window.moveHorizontal(-120); window.moveVertical(40); window.changeSize(40); window.makeVisible();

Next, create a new instance of the Square class called

“window”

Do the setup for “window”

wall: Square

size

120int

xPosition

170int

yPosition

140int

color

"red"Str

isVisible

truebool

window: Square

size

40int

xPosition

190int

yPosition

160int

color

"black"Str

isVisible

truebool

Slide 71

Java Requirements: Identifiers must consists of letters, digits, underscore (

_ ) or dollar sign ($) Identifiers must start with a letter - cannot start with

digit

Java Conventions (and my requirements): Class names start with capital letter - Use

PascalCasing Method / variable names should be clear and

descriptive – Use camelCasing Avoid one letter and meaningless identifier names

Naming

71

Slide 72

Looking Closer at the Code: Method Signatures

General Pattern Seems to Be:

public void methodName(sometimes parameters here)

Examples from Triangle classes in figures example :

public void makeVisible()

public void moveRight()

public void moveHorizontal(int distance)

public void changeSize(int newHeight, int newWidth)

public void changeColor(String newColor)

6-7

Slide 73

Demo

Open Lab-classes project

Make a new student Hey – this method takes parameters!

Try the getName method Returns a value

Change the student’s name & getName again

Look at Student Class Methods Can we tell which return values?

Slide 74

General Pattern:

public returnType methodName(sometimes parameters here)

Examples from Triangle class in figures example :

public void makeVisible()

public void moveHorizontal(int distance)

public void changeSize(int newHeight, int newWidth)

Method Signatures

74

Void means:“This space intentionally left

blank”

6-7

Slide 75

General Pattern:

public returnType methodName(sometimes parameters here)

Examples from Triangle class in figures example :

public void makeVisible()

public void moveHorizontal(int distance)

public void changeSize(int newHeight, int newWidth)

Examples from Student class in figures example :

public String getName()

public int getCredits()

public String getStudentID()

public void addCredits(int additionalPoints)

public void changeName(String replacementName)

Method Signatures6-7

Slide 76

public returnType methodName(sometimes parameters here)

returnType can be: primitive data type (like int or float or double or

char)

class (like Circle or Student) or

void (no return value)

Return values

76

14

Slide 77

Parameters

public returnType methodName(sometimes parameters here)

parameters are: Separated by commas

Each parameter consists of <parameter data type> &<parameter name>

<parameter data type> Can be a primitive data type or a class

<parameter name> The alphanumeric name of the parameter

Slide 78

IOOP Glossary Terms to Know

Terms to know for tests/quizzes (see class web site)

argument binary boolean class body class header

data type decimal floating-point number

hexadecimal instance variable

integer local variable

member method method body

method header

method result

method signature

octal parameter

primitive type

real number return statement

return type return value

Non-glossary terms to know

initialization declaration property

Note: the glossary definitions are complete ones, based on a full understanding

of the material which we might not yet have. However, there are elements of the definitions that you should be able to grasp from this material.