Difference between revisions of "KTurtle/C2/Grammar-of-TurtleScript/English"

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Hello everybody.
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'''Title slide'''
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Welcome to this tutorial on '''Grammar of TurtleScript''' in '''KTurtle'''.  
 
Welcome to this tutorial on '''Grammar of TurtleScript''' in '''KTurtle'''.  

Revision as of 16:47, 18 March 2013

I will zoom the program text for clear view.
Visual Cue Narration
Slide Number 1

Title slide

Hello everybody.

Welcome to this tutorial on Grammar of TurtleScript in KTurtle.

Slide Number 2

Learning Objectives

In this tutorial, we will learn
  • Grammar of Turtle script and
  • 'if'-'else' condition
Slide Number 3

System Requirement

To record this tutorial I am using,

Ubuntu Linux OS version. 12.04.

KTurtle version. 0.8.1 beta.

Slide Number 4

Pre-requisites

We assume that you have basic working knowledge of KTurtle

If not,

for relevant tutorials, please visit our website.

http://spoken-tutorial.org

Switch to KTurtle Application

Dash home >>In the Search bar

type KTurtle Click on the KTurtle icon.

Let's open a new KTurtle Application.

Click on Dash home.

In the Search bar, type KTurtle.

Click on the KTurtle icon.

Press CTRL+ALT+T >> open the terminal

>>type kTurtle >>press enter to open

We can also open KTurtle Application from the terminal.

Press CTRL+ALT+T simultaneously to open the terminal.

Type KTurtle and press enter KTurtle. Application opens

Slide Number 5

Turtle Script

First I will explain about TurtleScript
  • TurtleScript is a programming language
  • It has different types of words and symbols used for various purposes
  • It instructs Turtle what to do
Slide Number 6

Grammar of TurtleScript

Grammar of TurtleScript in KTurtle includes-
  • Comments
  • Commands
  • Numbers
  • Strings
  • Variables and
  • Boolean values
Slide Number 7

Numbers

Now we will see where to store numbers

Numbers can be stored in

  • Mathematical operators
  • Comparison operators and
  • Variables
Switch to KTurtle window First let's look at variables.

Variables are words that start with a ‘$’, for example $a.

In the editor they are highlighted with purple.

Using the assignment, equal to (=), a variable is given its content.

Variables can contain numbers $a=100.

strings $a=hello or

boolean values that is true or false $a=true

Variable keeps the content until program finishes execution or until it is reassigned to something else.

You can use variables, once assigned, just as if they are their content.

For example, consider the code typed in the editor.

$a = 2004

$b = 25

print $a + $b

Variable 'a' is assigned a value 2004.

Variable 'b' is assigned a value 25

print command commands Turtle to write something on the canvas.

print command takes numbers and strings as input.

print $a + $b commands Turtle to add two values and display them on the canvas.

Run the code Let's Run the code slow speed.

Value 2029 is displayed on the canvas

Slide Number 8

Mathematical operators

Let us next see the Mathematical Operators.

Mathematical operators include,

  • + (Addition)
  • - (Subtraction)
  • * (Multiplcation)
  • / (Division)
I already have a program in a text editor.

reset

canvassize 200,200

$add = 1 + 1

$subtract = 20 – 5

$multiply = 15 * 2

$divide = 30 /30

go 10,10

print $add

go 50,50

print $subtract

go 100,100 print $multiply

go 175,175

print $divide

go 0,0

I will copy the code from text editor and paste it into KTurtle editor.

Pause the tutorial and type the program into KTurtle editor.

Resume the tutorial after typing the program

I will Explain the code now
Highlight reset “reset” command sets Turtle to its default position
Highlight canvassize 200,200 canvassize 200,200 fix the width and height of the canvas to 200 pixels each.
Highlight $add = 1 + 1 value 1+1 is assigned to the variable $add,
Highlight $subtract = 20 – 5 20-5 is assigned to variable $subtract,
Highlight $multiply = 15 * 2 value 15 * 2 will be assigned to the variable $multiply.
Highlight $divide = 30 /30 30/30 is assigned to the variable $divide.
Highlight go 10,10 go 10,10 commands to Turtle to go 10 pixels left of canvas and 10 pixels from top of canvas
Run code

Point to the values

Let us now run this code in slow speed

Command which is getting executed is highlighted in the editor.

Turtle displays the values on the canvas at the specified positions.

Let us consider a simple example for using the comparison operator .

Type the commands being shown on the screen.

zoom text I will zoom the text to have clear view
Switch to Kturtle Window $answer = 10 > 3

print $answer

Here 10 is compared to 3 with the ’greater than’ operator.

The result of this comparison, the boolean value true is stored in the variable $answer and the value true is displayed.

Run the code Let's run this code

Turtle has displayed Boolean value true on the canvas.

Slide Number 9

Strings

Now lets see how Strings work in this application –
  • Strings can be put in variables like numbers
  • Strings cannot be used in mathematical or comparison operators
  • Strings are highlighted in red color
  • KTurtle identifies a line in double quote as a string
clear code I will clear the current code from editor.
Example of string For example:I am typing the print command followed by a string, “Hello”.

We See that the string is highlighted in Red color.

Run code When I run this piece of code, the turtle displays the string on the canvas.
Boolean Values Next I will explain about Boolean values.

There are only two boolean values: true and false.

For example Let's type the code

`if-else' Condition

$answer = 7<5

print $answer

Boolean value false is displayed on the canvas.

Boolean value false is assigned to variable $answer because 7 is larger than 5

“if-else” conditon. Let's next learn about “if-else” conditon.

‘if’ condition is executed only if the boolean value evaluates ‘true’

‘else’ condition is executed only if the ‘if’ condition is ‘false’ .

I already have a program in a text editor.
reset

$x=4

if $x>5 {

print $x

print “is greater than five”

}

else {

print $x

print “is smaller than six”

}

go 0,0

I will copy the code from text editor and paste it into KTurtle editor.

Pause the tutorial and type the program into KTurtle editor.

Resume the tutorial after typing the program

This code compares numbers 4 , 5 and 6 and displays the results accordingly.
Run code Let me now run this code.

Turtle has compared the variables 4 and 5.

and displayed the result 4 is smaller than 6 on the canvas .

With this we come to the end of this tutorial.

Let's summarize.

Slide Number 10

Summary

In this tutorial, we have learnt about
  • Grammar of Turtle script and
  • ‘if-else’ condition
Slide Number 11

Assignment

Now to the assignment part.

Solve an equation using

  • if - else condition
  • Mathematical and comparision operators
  • Display the results using “print” and “go” commands.
Slide Number 12

Assignment

To solve the assignment

  • Choose any four random numbers
  • Multiply two sets of random numbers
  • Compare the results using the comparison operators
  • Display the results
  • Display greater result at center of the canvas
  • You can choose any equation which you like.
Slide number 13

Acknowledgement

Watch the video available at

http://spoken-tutorial.org/What is a Spoken Tutorial

It summarises the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it

Slide Number 14 The Spoken Tutorial Project Team :

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to

contact@spoken-tutorial.org

Slide number 15 Spoken Tutorial Project is a part of the Talk to a Teacher project

It is supported by the National Mission on Education through ICT, MHRD, Government of India

More information on this Mission is available at this link

http://spoken-tutorial.org/NMEICT-Intro ]

Script is contributed by ITfC Bangaluru.

This is Madhuri Ganpathi from IIT Bombay signing off Thank you for joining.

Contributors and Content Editors

Madhurig

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