KTurtle/C2/Grammar-of-TurtleScript/English
| Visual Cue | Narration |
|---|---|
| Slide Number 1 |
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 |
| 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 |
| Grammar of TurtleScript | Grammar of TurtleScript in KTurtle includes-
Comments Commands Numbers Strings Variables and Boolean values |
| 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 |
| 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
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
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. Strin 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 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 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 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. 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. Summary In this tutorial, we have learnt about Grammar of Turtle script and ‘if-else’ condition 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. To solve the assignment Choose any four random numbers Multiply two sets of random numbers ompare 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 11 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 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 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. |
