Alice and Algorithms - World Class Educationamanno/Chapter_01_Intro_to_Alice Part 1.pdf · Alice...
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Alice and Algorithms Chapter 1 Part 1 1-1
Transcript of Alice and Algorithms - World Class Educationamanno/Chapter_01_Intro_to_Alice Part 1.pdf · Alice...
Alice and Algorithms
Chapter 1 Part 1
1-1
Reasons to Program
The joy of programming
To create a tool
To use your creativity abilities
For non programmers
o Learn a new way to think
Drawing course does same thing
o Helps problem solving skills
Finding answer to question
Determine how to perform a task
Alice
A modern programming tool
o 3-D graphics
o 3-D models of objects
People, animals, fantasy creatures, vehicles and backgrounds
Animation
o Objects can be moved around a 3D virtual world
o Similar to a video game or simulation
CD in book has Alice worlds from chapters
Can download Alice 2.4 from the webwww.alice.org
Alice Examples
Example Alice worlds
Demonstration video
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Origination of Alice
Named in honor of mathematician Charles Lutwige Dodson
o Was able to do complex math and logic
o Knew he needed to make things simple and fascinating for learner
Pen name was Lewis Carroll who wrote
o Alice in Wonderland
o Through the Looking Glass
Alice
Programming in Alice is like being a movie director, puppeteer, or choreographer in a 3D world
You create programs by dragging words and objects to editor with mouse
Kinds of Animations
Two kinds of animations
o Movie
Can tell a story
Passively watch animation
o Interactive
Active user clicks on mouse or types on keyboard
User actions are called events
Programming Terminology
Algorithm – step by step structure to solve a problem
Program – implementation of algorithm using a programming language
Instruction – an action to be performed
Pseudo code – loose set of instructions not tied to any program environment
o Like algorithm, but more geared toward programming
Computer
A device that follows instructions for manipulating and storing data
Computer program – set of instructions that computer follows to perform a task
o Instructions must be carefully written to follow a logical sequence
That is key – you need to think of the logical sequence you want the computer to follow
Running or executing program – when computer is performing instructions
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Algorithms
Algorithm
o Set of well-defined logical steps
o Must be performed in order to perform a task
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• Example: Making a cup of instant coffee
– Remove lid from coffee jar
– Put lid down on counter
– Remove 1 tsp of coffee from jar
– Place that coffee in a cup
– Add 8 oz of boiling water to cup
– Use teaspoon to stir water and coffee mixture
– Stir 10 revolutions
– Remove teaspoon from cup and place on counter
Is this adequate?
Is it detailed enough?
Is anything
ambiguous?
Algorithms
Algorithms are understandable by humans (natural language)
Computers understand machine language not natural language
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Blah
Blah
Blah
0110001001101100011000010110
1000001000000110001001101100
011000010110100000100000
0110001001101100011000010110
1000
Programming Languages
Programming languages are converted to machine language by
o Compiler – Instructions converted before executing program
o Interpreter – Each instruction is individually converted during execution, Ex: Alice
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Starting
…01010011011101000110000101110010011101000110
1001011011100110011100100000
out
…011011110111010101110100
With
…0111011101101001011101000110100000100000
Alice
…0100000101101100011010010110001101100101
Programming Languages
Operatorso + - * /
o Perform arithmetic and other functions on data
Syntax
o Set of rules that must be followed
o Similar to the set of rules that are followed when people speak a natural language
Program or code
o Consists of keywords, operators, punctuation arranged in proper logical sequence
o Save, compile, link, executable program is produced
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Checkpoint
What is a computer?
What is an algorithm?
What is a program?
What language is an algorithm written in?
What is the only language computers understand?
Why were programming languages invented?
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Class Exercise
Write an algorithm that explains how to make a Peanut Butter and Jelly sandwich
Assume the person does not know anything about how to make sandwiches
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Class Exercise
Describe the scene of two volleyball players on opposite sides of a volleyball net
Write algorithm to have one player serve the ball to another
Have the other player jump up with arms raised to block the ball
Have the ball fall to the ground across from the net
Make sure you reset the players to the resting position
Reset the server at same time as ball moves
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