KTurtle/C3/Control-Execution/English
| Visual Cue | Narration |
|---|---|
| Slide Number 1 |
Hello Everybody. Welcome to this tutorial on Control Execution in KTurtle |
| Slide Number 2
Learning Objectives |
In this tutorial, we will learn
'while' loop and 'for' loop |
| 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 >>Search bar appears>> In the Search bar type KTurtle |
Let's open a new KTurtle Application.
Click on Dash home. The Search bar appears. In the Search bar, type KTurtle. Click on the option. KTurtle Application opens. |
| Let me first explain about what is control execution. | |
| Slide Number 5
Control execution |
Control execution is controlling the flow of a program.
Different conditions are used to control program execution. |
| Slide Number 6
Loop |
Loop is a block of code is executed repeatedly untill a certain condition is satisfied.
Eg. “while” loop and “for” loop |
| Let's begin the tutorial with “while” loop | |
| Slide Number 7
“while” loop |
In the “while” loop, the code inside the loop repeats till boolean evaluates to 'false'. |
| Slide Number 8
Syntax of “while” loop |
Let me explain the structure of “while” loop.
while loop condition { do something with loop increment variable } |
| I already have the code in a text editor. | |
| #program to print a series of multiples 3 upto 30
reset $x=0 message"In while loop, code inside the loop repeats till boolean evaluates false" while $x<30 { $x=$x+3 fontsize 15 forward 20 print $x } |
Let me copy the program from text editor and paste it into KTurtle editor
|
| Let me zoom into the program text it may possibly be a little blurred. | |
| Let me explain the code. | |
| Highlight # | # sign comments a line written after it.
It means, this line will not be executed while running the program. |
| Highlight reset | reset command sets “Turtle” to its default position. |
| Highlight $x | $x=0 initialises the value of variable x to zero. |
| Highlight message" " | Message in a program is given within double quotes after the keyword message " "
“message” command takes “string” as input. It shows a pop-up dialog box containing text from the string. |
| Highlight while $x<30 | while $x<30 checks the “while” condition. |
| Highlight $x=$x+3 | $x=$x+3 increments the value of variable $x by 3 |
| Highlight fontsize 15 | fontsize 15 sets the font size used by print command.
Fontsize takes number as input, set in pixels. |
| Highlight forward 20 | forward 20 commands “Turtle” to move 20 steps forward on the canvas. |
| Highlight print $x | print $x displays the value of variable x on the canvas. |
| Run the program | Let me click on the “Run” button to run the program.
A message dialog box pops up. Let me click OK. |
| Run the program | Multiples of 3 from 3 to 30 are displayed on the canvas.
“Turtle” moves 20 steps forward on the canvas. |
| Let's next work with “for” loop | |
| Slide Number 9
"for" loop |
“for” loop is a counting loop.
Every time the code inside “for” loop is executed, variable value is incremented, till it reaches the end value. |
| Slide Number 10
Syntax of “for” loop |
Let me explain the structure of “for” loop.
for variable = start number to end number { Statement} |
| Clear the editor and canvas | Let me clear the current program.
Let me type clear command and run to clean the canvas. |
| #program print to sum of first 15 natural numbers
reset' $r=0 for $x= 1 to 15{ $r=$x*($x+1)/2 fontsize 18 print $r forward 15 } go 10,250 wait 2 print "Sum of first 15 natural numbers ="+$r |
Let me copy the program and paste it into KTurtle editor
Please resume the turtorial after typing the program. |
| Let me zoom into the program text it may possibly be a little blurred. | |
| Let me explain the code. | |
| Highlight # | # sign comments a line written after it. |
| Highlight reset | reset command sets “Turtle” to default position. |
| Highlight $r=0 | $r=0 initialises the value of variable r to zero. |
| Highlight for $x= 1 to 15 | for $x= 1 to 15 checks “for” condition from 1 to 15. |
| Highlight $r=$x*($x+1)/2 | $r=$x*($x+1)/2 calculates the value of variable r. |
| Highlight fontsize 18 | fontsize 18 sets the font size used by print command. |
| Highlight print $r | print $r displays the variable r. |
| Highlight forward 15 | forward 15 moves Turtle 15 steps foward. |
| Highlight go 10,250 | go 10,250 commands Turtle to go 10 pixels from left of canvas and 250 pixels from top of canvas. |
| Highlight wait 2 | “Turtle” displays all print commands without any time gap.
“Wait 2” command makes Turtle to “wait” for 2 seconds before executing next command. |
| print "Sum of first 15 natural numbers ="+$r | “print” command displays the “string” within double quotes and also displays variable $r. |
| Run the program | Let me click the “ Run” button to run the program.
A series of sum of first 15 numbers and sum of first 15 natural numbers is displayed on the canvas. Turtle moves 15 steps forward. |
| With this we come to end of this tutorial. | |
| Slide Number 11
Summary |
Let us summarize.
In this tutorial we have learnt to use,
|
| Slide Number 12
Assignment |
As an assignment I would like you to write programs to evaluate
|
| Slide number 13 | 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 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 ] This is Madhuri Ganpathi from IIT Bombay signing off Thank you for joining |
