KTurtle/C3/Special-Commands-in-KTurtle/English-timed

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Visual Cue Narration
Slide Number 1

Title slide

Hello everybody.

Welcome to this tutorial on Special Commands in KTurtle.

Slide Number 2

Learning Objectives

In this tutorial, we will learn about
  • “learn” command and
  • “random” Command
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.

Let's first look at “learn” command
Slide Number 5

learn command

learn is special command as it is used to create your own commands.

'learn' Command you create can take input and return output.

Zoom text I will zoom the program text to have a clear view.

Switch to Kturtle Window

repeat 4

{

forward 10

turnleft 90

}

Let us take a look at how a new command is created.

Let's type a code in the editor to draw a square:

repeat 4 within curly brackets

{ forward 10

turnleft 90

}

here the number 10 specfies the length of the side of the square.

Highlight learn and square commands Now let's learn the commands involved to draw a square, using the learn command.

We will name of this set of commands to draw a square as square.

The command 'learn' is followed by the name of the command to be learnt, in this case it is a square.

Type the code Let's type the following code

learn space square $x

let's include the learn command within curly brackets {

repeat 4 {

let's repace number 10 by $x

forward $x

turnleft 90 } }

Highlight square command New command that we have defined is called square.

square takes one input argument, $x to set the size of the square.

Note that when you run this code, square returns no output.

The command learn is just 'learning' the other command square to be used later.

square command can now be used like a normal command in the rest of the code.

Type the code Let me add few more lines here.

Let's type

learn square $x

{

repeat 4

{

forward $x

turnleft 90

} }

go 200,200

square 100

Run the code Let's click on Run code

Turtle draws a square on the canvas.

The command square can be used any where any number of times in the program.

Replace 100 by 50. Let's now replace 100 by 50.
Run the code Let's run again

Turtle draws an another square with dimension 50.

Please note that this command can be used only within the scope of this program

Clear code I will clear the current code from editor.

Type “clear” command and Run to clean the canvas.

Next we will learn about “random” command.
Slide Number 6

"random" command

“random” command takes input and gives output.

Syntax for this command is “random X,Y”

where X and Y are two inputs.

X sets minimum output and Y sets maximum.

Output is a randomly chosen number between X and Y.

Let's put the “random” command to use in the application.

I already have the code in a text editor.

Let me explain the code.

Highlight reset “reset” command sets Turtle to default position
Highlight random 1,20 Here, the command random 1,20 selects a random number which is equal or greater than 1 and equal or lesser than 20,

and assigns it to the variable x.

Highlight repeat 36

{

forward $x

turnleft 10 }

The repeat command and the commands within curly brackets draw a circle
reset

$x=random 1,20

repeat 36

{

forward $x

turnleft 10

}

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

Pause the tutorial and type the program into your KTurtle editor.

Resume the tutorial after typing the program

Run the code When we run this code,

Turtle draws a circle which is between 1 and 20 on the canvas.

Let us execute this code a few times,

and you can see that a circle with a different size is generated each time.

Every time you exceute this code, a circle with a different radius is drawn on the canvas.

Let us now use both the learn and random commands in an example.

clear current code I will clear the current code and Run to clean the canvas.
I already have a code in the Text editor.

I will explain the code.

Highlight reset

“reset” command sets Turtle to its default position.
Highlight canvassize 300,300 canvassize 300,300 sets the width and height of the canvas to 300 pixels each.
Highlight $R, $G, and $B $R, $G, and $B are three variables to which I am assigning random values between 0 and 255.
Highlight canvascolor $R,$G,$B , In the command canvascolor $R,$G,$B ,

the Red-Green-Blue combination is replaced by the values assigned to the variables R, G, and B in the previous step.

The canvas color is randomly set when this command is executed.

Highlight $red, $green and $blue $red, $blue, $green are another set of variables

to which random values between 0 and 255 are assigned randomly.

pencolor $red, $green, $blue the Red-Green-Blue combination values are replaced by the variables

$red, $green and $blue to which random values were assigned in the previous step.

Highlight pencolor $red,$blue,$green The color of the pen is also set randomly when the command is executed.
Highlight penwidth 2 penwidth 2 sets the width of the pen to 2 pixels.
code to a circle Next I have entered the code to learn to draw a circle.

Here $x represents the size of the circle.

The repeat command followed by the code in curly brackets draws a circle.

Highlight go commands and circle commands

The next set of commands that is the go commands followed by the circle commands draws circles with the specified sizes.

Example circle For example:

“ circle 5” draws a circle of size 5

At the co-ordinates X and Y specified in the go command.

For each circle, I have specified different positions on the canvas.

reset

canvassize 300,300

$R= random 0,255

$G=random 0,255

$B=random 0,255

canvascolor $R,$G,$B

$red=random 0,255

$blue=random 0,255

$green=random 0,255

pencolor $red,$blue,$green

penwidth 2

learn circle $x{

repeat 36{

forward $x

turnleft 10 } }

go 85,85

circle 5

go 115,115

circle 5

go 145,145

circle 5

go 190,190

circle 5

go 220,220

circle 10

go 0,0

I will copy this code from text editor and paste it into KTurtle's editor.

Pause the tutorial and type the program into ypur KTurtle editor.

Resume the tutorial after typing the program.

Execute code I will execute this code in Fullspeed.

You can execute your code at any of the speeds specified in the Run option.

I will run this code few more times.

You can see the difference in randomly set values of pen color and canvas color.

Note the change in the color of the pen and the canvas on each execution.

You can execute the code how many ever times you want and note the change in the randomly set values.

With this we come to the end of this tutorial.

Let's summarize

Summary In this tutorial we have learnt about,
  • “learn” command and
  • “random” command.
Switch to Slide 6

Switch to KTurtle Window & Show Assignment

As an assignment for you to solve,
  • Using the learn command, draw a
  • pentagon
  • square
  • rectangle
  • hexagon on the four corners of your canvas and a
  • circle at the centre of the canvas.
  • Using the “random” command create various colors and
  • Customize your geometric shapes and canvas.
Slide number 11

Acknowledgement

Watch the video available at this URL

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 12 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 13 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 ]

The script is contributed by IT for change, Bangaluru.

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

Contributors and Content Editors

Krupali, Madhurig, PoojaMoolya, Pratik kamble, Pravin1389, Sandhya.np14, Sneha

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