Download Learn to Program with Scratch PDF

TitleLearn to Program with Scratch
LanguageEnglish
File Size18.4 MB
Total Pages291
Table of Contents
                            About the Author
About the Technical Reviewer
Acknowledgments
Introduction
	Whom This Book Is For
	A Note to the Reader
	Features
	Organization of This Text
	Conventions Used
	Online Resources
	Errata and Updates
Chapter 1: Getting Started
	What Is Scratch?
	Scratch Programming Environment
	Sprite List
	The Stage
	try it out 1-3
		Blocks Tab
		Scripts Area
	try it out 1-5
		Costumes Tab
	try it out 1-7
	Sprite Info
	Backdrops Tab
	Sounds Tab
	Toolbar
	Paint Editor
		Setting the Center of an Image
	try it out 1-10
		Setting Transparent Color
	Your First Scratch Game
		Step 1: Prepare the Backdrop
		Step 2: Add the Paddle and Ball
		Step 3: Start the Game and Get Your Sprites Moving
	try it out 1-11
		Step 4: Spice It Up with Sound
	Scratch Blocks: An Overview
	Arithmetic Operators and Functions
		Arithmetic Operators
		Random Numbers
		Mathematical Functions
	Summary
	Problems
Chapter 2: Motion and Drawing
	Using Motion Commands
		Absolute Motion
		Relative Motion
	try it out 2-2
		Other Motion Commands
	Pen Commands and Easy Draw
	try it out 2-3
	try it out 2-4
	The Power of Repeat
	try it out 2-5
		Rotated Squares
		Exploring with Stamp
	try it out 2-7
	Scratch Projects
		Get the Money
		Catching Apples
	More on Cloned Sprites
	Summary
	Problems
Chapter 3: Looks and Sound
	The Looks Palette
		Changing Costumes to Animate
	try it out 3-1
	Image Effects
	Sprites That Speak and Think
	try it out 3-3
		Layers
	The Sound Palette
		Playing Audio Files
	Controlling Sound Volume
	Composing Music
	Playing Drums and Other Sounds
	try it out 3-5
	Setting the Tempo
	Scratch Projects
		Dancing on Stage
		Fireworks
	Summary
	Problems
	Size and Visibility
Chapter 4: Procedures
	Message Broadcasting and Receiving
		Sending and Receiving Broadcasts
		Message Broadcasting to Coordinate Multiple Sprites
	Creating Large Programs in Small Steps
		Creating Procedures with Message Broadcasting
		Building Your Own Block
		Passing Parameters to Custom Blocks
	try it out 4-1
		Using Nested Procedures
	try it out 4-2
	Working with Procedures
		Breaking Programs Down into Procedures
	try it out 4-3
		Building Up with Procedures
	Summary
	Problems
Chapter 5: Variables
	Data Types in Scratch
		What’s in the Shape?
		Automatic Data Type Conversion
	Introduction to Variables
		What Is a Variable?
		Creating and Using Variables
	Try It Out 5-1
		The Scope of Variables
		Changing Variables
	Try It Out 5-2
		Variables in Clones
	Displaying Variable Monitors
	Using Variable Monitors in Applications
		Simulating Ohm’s Law
	Try It Out 5-3
		Demonstrating a Series Circuit
		Visualizing a Sphere’s Volume and Surface Area
	Try It Out 5-5
		Drawing an n-Leaved Rose
	Try It Out 5-6
		Modeling Sunflower Seed Distribution
	Getting Input from Users
	Performing Arithmetic Operations
	Reading Characters
	Reading a Number
	Summary
	Problems
Chapter 6: Making Decisions
	Comparison Operators
		Evaluating Boolean Expressions
		Comparing Letters and Strings
	Decision Structures
		The if Block
		Using Variables as Flags
		The if/else Block
		Nested if and if/else Blocks
		Menu-Driven Programs
	Logical Operators
		The and Operator
		The or Operator
		The not Operator
		Using Logical Operators to Check Numeric Ranges
	Scratch Projects
		Guess My Coordinates
	try it out 6-1
		Triangle Classification Game
	try it out 6-2
		Line Follower
		Equation of a Line
	Other Applications
	Summary
	Problems
Chapter 7: Repetition: A Deeper Exploration of Loops
	More Loop Blocks in Scratch
		The repeat until Block
	try it out 7-1
		Building a forever if Block
	try it out 7-2
	Stop Commands
	try it out 7-3
		Ending a Computational Loop
		Validating User Input
	Counters
		Check a Password
		Counting by a Constant Amount
	Revisiting Nested Loops
	Recursion: Procedures That Call Themselves
	Scratch Projects
		Analog Clock
	Bird Shooter Game
	try it out 7-8
		Free-Fall Simulation
	try it out 7-9
		Projectile Motion Simulator
	try it out 7-10
		Other Applications
	Summary
	Problems
Chapter 8: String Processing
	Revisiting the String Data Type
		Counting Special Characters in a String
		Comparing String Characters
	try it out 8-1
	String Manipulation Examples
		Igpay Atinlay
	try it out 8-2
		Fix My Spelling
	try it out 8-3
		Unscramble
	Scratch Projects
		Shoot
	try it out 8-4
		Binary to Decimal Converter
	try it out 8-5
		Hangman
	try it out 8-7
		Fraction Tutor
	try it out 8-8
	Summary
	Problems
Chapter 9: Lists
	Lists in Scratch
		Creating Lists
	try it out 9-1
		List Commands
	try it out 9-2
		Bounds Checking
	Dynamic Lists
		Filling Lists with User Input
		Creating a Bar Chart
	try it out 9-3
	Numerical Lists
		Finding Min and Max
		Finding the Average
	try it out 9-5
	Searching and Sorting Lists
		Linear Search
		Frequency of Occurrence
	try it out 9-6
		Bubble Sort
		Finding the Median
	Scratch Projects
		The Poet
	try it out 9-8
		Quadrilateral Classification Game
	try it out 9-9
		Math Wizard
		Flower Anatomy Quiz
	Other Applications
	Summary
	Problems
Appendix: Sharing and 
Collaboration
	Creating a Scratch Account
	Using the Backpack
	Creating Your Own Project
		Starting a New Project
		Remixing a Project
		The Project Page
		Sharing Your Project
Index
About the Online Resources
Updates
                        
Document Text Contents
Page 1

Layer 5


L E A R N T O
P R O G R A M W I T H

S C R A T C H

L E A R N T O
P R O G R A M W I T H

S C R A T C H
A V I S U A L I N T R O D U C T I O N T O P R O G R A M M I N G

W I T H G A M E S , A R T , S C I E N C E , A N D M A T H

M A J E D M A R J I

C
O

V E R
S

S
C

R
A T C

H
2

SH
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$34.95 ($36.95 CDN)

www.nostarch.com

TH E F I N EST I N G E E K E NTE RTA I N M E NT ™

Scratch is a fun, free, beginner-friendly programming
environment where you connect blocks of code to build
programs. While most famously used to introduce kids
to programming, Scratch can make computer science

countless lines of code in a cryptic programming lan-

script, and with a single click, you can even test any
coded blocks plainly show each logical step in a given

part of your script to check your logic. You’ll learn
how to:

approachable for people of any age. Rather than type

M
A

R
JI

L
E

A
R

N
T

O
P

R
O

G
R

A
M

W
IT

H
S

C
R

A
T

C
H

L
E

A
R

N
T

O
P

R
O

G
R

A
M

W
IT

H
S

C
R

A
T

C
H

guage, why not use colorful command blocks and
cartoon sprites to create powerful scripts?

• Harness the power of repeat loops and recursion

• Use if/else statements and logical operators to make
decisions

program
• Store data in variables and lists to use later in your

• Read, store, and manipulate user input

Hands-on projects will challenge you to create an

• Implement key computer science algorithms like linear
searches and bubble sorts

Ohm’s law simulator, draw intricate patterns, program
sprites to mimic line-following robots, create arcade-style
games, and more! Each chapter is packed with detailed
explanations, annotated illustrations, guided examples,
lots of color, and plenty of exercises to help the lessons

Wayne State University in Michigan. He holds a PhD

A B O U T T H E A U T H O R

Majed Marji is a senior development engineer at
General Motors and an adjunct faculty member at

in electrical engineering from Wayne State University
and an MBA in strategic management from Davenport
University.

stick. Learn to Program with Scratch is the perfect place
to start your computer science journey.

G U I D E T O
( A N D P A I N L E S S )
A N I L L U S T R A T E D

C O M P U T E R
S C I E N C E

G U I D E T O
( A N D P A I N L E S S )
A N I L L U S T R A T E D

C O M P U T E R
S C I E N C E

In Learn to Program with Scratch, author Majed Marji
uses Scratch to explain the concepts essential to solving
real-world programming problems. The labeled, color-

www.it-ebooks.info

http://www.it-ebooks.info/

Page 146

124 Chapter 6

In many programming situations, however, you may want to alter this
sequential flow of program execution. If you were writing an application to
tutor children in basic arithmetic, you’d want to execute certain blocks to
reward correct answers and a completely different set of blocks for wrong
answers (to reveal the right answer or offer another chance, for example).
Your script can decide what to do next by comparing the student’s input
with the correct answer. This is the basis of all decision-making tasks.

In this chapter, we’ll explore the decision-making commands available
in Scratch and write several programs that use these commands to test
inputs and perform different actions.

First, I’ll introduce you to Scratch’s comparison operators and show
how you can use them to compare numbers, letters, and strings. Then, I’ll
introduce the if and if/else blocks and explain their key role in decision
making. You’ll also learn how to test multiple conditions using nested if and
if/else blocks and write a menu-driven program to put these blocks into
action. After that, I’ll introduce logical operators as an alternative way to
test multiple conditions. In the last section, we’ll write several interesting
programs based on all of the concepts you’ve learned so far.

comparison operators
You make decisions every day, and each decision normally leads you to per-
form certain actions. You may think, for example, “If that car is less than
$2,000, I’ll buy it.” You then ask about the car’s price and decide whether
or not you want to buy it.

You can make decisions in Scratch, too. Using comparison operators,
you can compare the values of two variables or expressions to determine
whether one is greater than, less than, or equal to the other. Comparison
operators are also called relational operators because they test the relation-
ship between two values. The three relational operators supported in
Scratch are shown in Table 6-1.

Table 6-1: Relational Operators in Scratch

Operator Meaning Example

greater than

Is price greater than 2,000?

less than

Is price less than 2,000?

equal to

Is price equal to 2,000?

www.it-ebooks.info

http://www.it-ebooks.info/

Page 291

Layer 5


L E A R N T O
P R O G R A M W I T H

S C R A T C H

L E A R N T O
P R O G R A M W I T H

S C R A T C H
A V I S U A L I N T R O D U C T I O N T O P R O G R A M M I N G

W I T H G A M E S , A R T , S C I E N C E , A N D M A T H

M A J E D M A R J I

C
O

V E R
S

S
C

R
A T C

H
2

SH
ELV

E IN
:

CO
M

PU
TERS/

PRO
G

R
A

M
M

IN
G

LAN
G

U
AG

ES

$34.95 ($36.95 CDN)

www.nostarch.com

TH E F I N EST I N G E E K E NTE RTA I N M E NT ™

Scratch is a fun, free, beginner-friendly programming
environment where you connect blocks of code to build
programs. While most famously used to introduce kids
to programming, Scratch can make computer science

countless lines of code in a cryptic programming lan-

script, and with a single click, you can even test any
coded blocks plainly show each logical step in a given

part of your script to check your logic. You’ll learn
how to:

approachable for people of any age. Rather than type

M
A

R
JI

L
E

A
R

N
T

O
P

R
O

G
R

A
M

W
IT

H
S

C
R

A
T

C
H

L
E

A
R

N
T

O
P

R
O

G
R

A
M

W
IT

H
S

C
R

A
T

C
H

guage, why not use colorful command blocks and
cartoon sprites to create powerful scripts?

• Harness the power of repeat loops and recursion

• Use if/else statements and logical operators to make
decisions

program
• Store data in variables and lists to use later in your

• Read, store, and manipulate user input

Hands-on projects will challenge you to create an

• Implement key computer science algorithms like linear
searches and bubble sorts

Ohm’s law simulator, draw intricate patterns, program
sprites to mimic line-following robots, create arcade-style
games, and more! Each chapter is packed with detailed
explanations, annotated illustrations, guided examples,
lots of color, and plenty of exercises to help the lessons

Wayne State University in Michigan. He holds a PhD

A B O U T T H E A U T H O R

Majed Marji is a senior development engineer at
General Motors and an adjunct faculty member at

in electrical engineering from Wayne State University
and an MBA in strategic management from Davenport
University.

stick. Learn to Program with Scratch is the perfect place
to start your computer science journey.

G U I D E T O
( A N D P A I N L E S S )
A N I L L U S T R A T E D

C O M P U T E R
S C I E N C E

G U I D E T O
( A N D P A I N L E S S )
A N I L L U S T R A T E D

C O M P U T E R
S C I E N C E

In Learn to Program with Scratch, author Majed Marji
uses Scratch to explain the concepts essential to solving
real-world programming problems. The labeled, color-

www.it-ebooks.info

http://www.it-ebooks.info/

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