View source for KTurtle/C3/Special-Commands-in-KTurtle/English-timed

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!Visual Cue
!Narration
|-
||00:01
||Hello everybody. Welcome to this tutorial on '''Special Commands'''  in '''KTurtle.''' 
|-
||00:08
||In this tutorial, we will learn about 

* '''“learn”''' command and

* '''“random”''' Command
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||00:15
||To record this tutorial I am using, '''Ubuntu Linux''' OS version. 12.04. '''KTurtle''' version. 0.8.1 beta. 
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|| 00:28
||We assume that you have basic working knowledge of KTurtle 

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|| 00:33 
||If not, for relevant tutorials, please visit our website. '''http://spoken-tutorial.org''' 
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|| 00:39
||Let's open a new KTurtle Application. 

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|| 00:42
||Click on '''Dash home.'''  

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|| 00:44 	
||In the Search bar, type '''KTurtle'''. 

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|| 00:47
||Click on the''' KTurtle''' icon. 
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||00:50
||Let's first look at  “learn” command
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|| 00:53
||''' learn''' is a special command  as it is used to create your own commands. 

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|| 01:01
||'learn' Command  can takes input and returns output. 
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||01:05
||Let's take a look at how a new command is created.
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||01:10
||Let me zoom the program text to have a clear view.
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||01:14
||Let's type a code in the editor to draw a square: 

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|| 01:19
||'''repeat 4''' within curly brackets

{ 
'''forward 10''' 

'''turnleft 90''' 

}

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|| 01:31
||Here the number '''10''' specfies the length of the side of the square.
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|| 01:37
||Now let's  learn the commands involved to draw a square, using the '''learn''' command. 

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|| 01:45
||We will name of this set of commands to draw a square as '''square'''. 

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|| 01:50
||The command ''''learn'''' is followed by the name of the command to be learnt, in this case it is a '''square.''' 
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|| 01:59
||Let us type the following code

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|| 02:02
||'''learn''' space '''square''' space '''$x''' 

|-
|| 02:10
||let's include curly brackets
 

|-
|| 02:13
||let's replace '''10''' by '''$x'''

'''forward $x''' 

'''turnleft 90''' 
} 
} 
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|| 02:19
||New command that we have defined  is called '''square.''' 

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|| 02:23
||'''square''' takes one input argument,  '''$x''' to set the size of the square. 

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|| 02:31
||Note that when you run this  code,''' square''' returns no output. 

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|| 02:37
||The command '''learn''' is just 'learning' other command ''' square''' to be used later. 

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|| 02:43
||'''square''' command can now be used like a normal command in the rest of the code. 
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|| 02:51
||Let me add few more lines here. 
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|| 02:54
||Let's type



'''go 200,200''' 

'''square 100''' 

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|| 03:04
||Using the command '''square 100''' Turtle draws a square of dimension 100.
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|| 03:11
||Let's  the Run code now

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|| 03:13
||'''Turtle''' draws a square on the canvas.

|-
|| 03:17
||Let's  now replace 100 by 50.
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|| 03:22
||Let's run again

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|| 03:23
||'''Turtle''' draws an another '''square''' with dimension 50.

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|| 03:28
||Please note that this command can be used only within the scope of this program
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|| 03:35
||I will clear the current code from editor.

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|| 03:38
||Type “clear” command and Run to clean the canvas.
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||03:44	
||Next we will  learn about “random” command.
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|| 03:48
||'''random''' command takes input and returns output. 
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|| 03:52
|| Syntax for the random command is “random X,Y” 

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|| 03:57
|| where X and Y are two inputs. 

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|| 04:01
|| X sets minimum output and Y sets maximum output.

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|| 04:07
|| Output is randomly chosen number between X and Y. 
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||04:13
||Let's put the “random” command to use in the application. 
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|| 04:18
||I already have acode in a text editor.

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|| 04:22
||I will explain the code.
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|| 04:24
||“reset” command sets '''Turtle''' to default position
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|| 04:29
||Here, the command '''random 1,20''' selects a random number which is equal or greater than 1 and equal or less than 20, and assigns it to the variable x. 
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|| 04:44
||'''repeat''' command and the commands begins curly brackets draw a circle
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|| 04:51
||I will copy the code from text editor and paste it into '''KTurtle's''' editor.

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|| 04:58
||Pause the tutorial and type the program into your '''KTurtle''' editor.

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|| 05:03
||Resume the tutorial after typing the program
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|| 05:08
||When we run this code, 

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|| 05:10	
||'''Turtle''' draws a  circle with radius  between 1 and 20  on the canvas. 

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|| 05:16
||Let us execute this code a few times,

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|| 05:20
||You can see that a circle with a different size is generated each time. 

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|| 05:26
||Every time you execute this code, a circle with a different radius is drawn on the canvas. 
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||05:33
||Let us now use both the '''learn''' and '''random''' commands in an example. 
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|| 05:39
||I will clear the current code  from the editor   type '''clear''' command and '''Run''' to clean the canvas.
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|| 05:48
||I already have a program in the Text editor.

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|| 05:52
||I will explain the code now.
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||05:55
||“reset” command sets Turtle to its default position.
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|| 06:00 
||'''canvassize 300,300''' sets the width and height of the canvas to 300 pixels each. 
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|| 06:09
||'''$R, $G,''' and '''$B''' are three variables to which I am assigning random values between 0 and 255. 
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|| 06:19
||In the command '''canvascolor $R,$G, and $B''' , 

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|| 06:23
||the Red-Green-Blue combination is replaced by the values assigned to the  variables R, G, and B in the previous step. 

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|| 06:34
||The canvas color is randomly  set  when this command is executed. 
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|| 06:41
||'''$red, $blue, $green''' are another set of variables 

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|| 06:45
||to which random values between 0 and 255 are assigned randomly. 

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|| 06:53
||'''pencolor  $red, $blue and $green''' the Red-Blue -Green combination values are replaced by the variables 
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|| 07:02
|| '''$red''', '''$green''' and '''$blue''' to which random values were assigned 
in the previous step. 
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|| 07:10
||The color of the pen is also set randomly when the command is executed. 
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|| 07:18
||'''penwidth 2''' sets the width of pen to 2 pixels. 
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||07:25
|| Next I have entered the code to learn to draw a circle. 

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|| 07:30
||Here '''$x''' represents the size of the circle. 

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|| 07:35
||'''repeat''' command followed by the code in curly brackets draws a circle.
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|| 07:43
||The next set of commands that is  '''go''' commands followed by '''circle''' commands draw circles with the specified sizes. 
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|| 07:54
||For example: circle with size 5 draws a circle with size 5 

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|| 08:01
||At the co-ordinates  specified at X and Y positions in the '''go''' command. 

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|| 08:09
||For each circle, I have specified different positions on the canvas. 
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|| 08:16
||I will copy the code from text editor and paste it into KTurtle's editor.

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|| 08:23
||Pause the tutorial here and type the program into your KTurtle editor.

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|| 08:29
||Resume the tutorial after typing the program.
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|| 08:33
||I will execute this code in''' Fullspeed'''.

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|| 08:37
||You can execute this code at any of the speeds specified in the ''' Run''' option. 

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|| 08:43
||I will run this code a few times.

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|| 08:46
||You can see the difference in randomly set values of pen color and canvas color. 

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|| 08:54
||Note the change in the color of the pen and the canvas on each execution. 

|-
|| 09:01
||You can execute the code how many ever times you want and note the changes  in 
the randomly set values of the pen and canvas. 
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||09:15
||With this we come to the end of this tutorial.
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|| 09:20
||Let's summarize
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||09:22
||In this tutorial we have learnt about,

* “learn” command  and

* “random” command.
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||09:30
||As an assignment for you to solve, 

|-
|| 09:32
||Using  '''learn''' command, draw a 

* pentagon

* square

* rectangle

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|| 09:39
||hexagon on all four corners of your canvas and

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|| 09:45
|| A circle at the centre of the canvas. 

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|| 09:49
|| Using the “random” command create various colors and 

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|| 09:55
|| Customize your geometric shapes and canvas. 
|-
||  10:00 
||Watch the video available at this URL '''http://spoken-tutorial.org/What is a Spoken Tutorial'''
|-
|| 10:04
||It summarises the Spoken Tutorial project

|-
|| 10:08
||If you do not have good bandwidth, you can download and watch it 
|-
|| 10:13
||The Spoken Tutorial Project Team : 

|-
|| 10:15
||Conducts workshops using spoken tutorials

|-
|| 10:19
||Gives certificates to those who pass an online test 

|-
|| 10:22
||For more details, please write to  '''contact@spoken-tutorial.org''' 
|-
|| 10:29
||Spoken Tutorial Project is a part of the Talk to a Teacher project 

|-
|| 10:33
||It is supported by the National Mission on Education through ICT, MHRD, Government of India

|-
|| 10:40
||More information on this Mission is available at this link  '''http://spoken-tutorial.org/NMEICT-Intro ]''' 

|-
|| 10:46
||This script is contributed by '''IT for change, Bangaluru.'''

|-
|| 10:50
||This is Madhuri Ganpathi from '''IIT Bombay''' signing off. Thank you for joining. 
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