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

Hello everybody.

Welcome to this tutorial on Grammar of TurtleScript in KTurtle.

Learning Objectives

• Grammar of Turtle script and

• 'if'-'else' condition

System Requirement

Ubuntu Linux OS version. 12.04.

KTurtle version. 0.8.1 beta.

Pre-requisites

If not,

for relevant tutorials, please visit our website.

http://spoken-tutorial.org

Dash home >>In the Search bar

type KTurtle Click on the KTurtle icon.

Click on Dash home.

In the Search bar, type KTurtle.

Click on the KTurtle icon.

>>type kTurtle >>press enter to open

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

Type KTurtle and press enter KTurtle. Application opens

Turtle Script

• 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

• Comments

• Commands

• Numbers

• Strings

• Variables and

• Boolean values

Numbers

Numbers can be stored in

• Mathematical operators

• Comparison operators and

• 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.

$a = 2004

$b = 25

print $a + $b

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.

Value 2029 is displayed on the canvas

Mathematical operators

Mathematical operators include,

• + (Addition)

• - (Subtraction)

• * (Multiplcation)

• / (Division)

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

Pause the tutorial and type the program into KTurtle editor.

Resume the tutorial after typing the program

Point to the values

Command which is getting executed is highlighted in the editor.

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

Type the commands being shown on the screen.

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.

Turtle has displayed Boolean value true on the canvas.

Strings

• 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

We See that the string is highlighted in Red color.

There are only two boolean values: true and false.

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

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

$x=4

if $x>5 {

print $x

print “is greater than five”

}

else {

print $x

print “is smaller than six”

}

go 0,0

Pause the tutorial and type the program into KTurtle editor.

Resume the tutorial after typing the program

Turtle has compared the variables 4 and 5.

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

Let's summarize.

Summary

• Grammar of Turtle script and

• ‘if-else’ condition

Assignment

Solve an equation using

• if - else condition

• Mathematical and comparision operators

• Display the results using “print” and “go” commands.

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.

Acknowledgement

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

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to

contact@spoken-tutorial.org

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.