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Revision as of 17:59, 10 January 2013
| Visual Cue | Narration |
|---|---|
| Slide Number 1 | Hello everybody.
Welcome to this tutorial on Common Errors in KTurtle. |
| Slide Number 2
Learning Objectives |
In this tutorial, we will learn about
|
| Slide Number 3
System Requirement |
To record this tutorial I am using,
Ubuntu Linux OS v. 12.04. KTurtle v. 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 |
| First I will explain about "Types of errors". | |
| Slide Number 5
Syntax Errors |
A syntax error is a violation of grammatical rules, of a programming language.
Compilation fails when a program has syntax errors. Syntax errors are easy to find and fix. For Example:
|
| Switch to KTurtle Application
Dash home >>Search bar appears>> In the Search bar type KTurtle Click on the KTurtle icon. |
Let's open a new KTurtle Application.
Click on Dash home. The Search bar appears. In the Search bar, type KTurtle. Click on the KTurtle icon. |
| Let's begin the tutorial with some types of syntax errors. | |
| I already have a program in a text editor. | |
| reset
$a=ask "enter any number and click Ok" $r = ask "enter any number and click ok" $n = ask "enter any number and click ok" $T = $a*($r^$n)*($r^-1) print $T |
Let copy the program into Kturtle Editor.
Please pause the tutorial and type the program into KTurtle editor
|
| Zoom text | Let me zoom into the program text.
It may possibly be a little blurred. |
| To explain error in the program, I will delete part of the code. | |
| Highlight
$a=ask "enter any number and click Ok" |
Here, I will delete the line $a=ask "enter any number and click Ok" |
| Run the program | Let's Click on Run button to run the program
Complier shows the following error, The variable "$a" was used without first being assigned to a value. |
| Replace the deleted line | I will replace the deleted line $a=ask "enter any number and click Ok" |
| Run the program | Let's run again
press F5 key to run the program We see that the program runs without errors. |
| Next let's look at another type of error. | |
| I already have a program in a text editor. | |
| reset
$degree=ask "enter any angle value and click OK" $radian=(pi/180)*$degree go 50,50 print "Value in radians is"+ " " +$radian spritehide |
Let me copy the program into Kturtle Editor
Please pause the tutorial and type the program into KTurtle editor
|
| Zoom text | Let me zoom into the program text.
It may possibly be a little blurred. |
| Highlight $ | Let's delete $ signs in the program. |
|
Run the program |
Let's Click on Run button to run the program.
Complier shows the following error, you cannot put “=” here |
| Replace $ signs | Let's replace the $ signs and run again.
Program runs properly |
| Highlight "Value in radians is" | Let's remove one of the quotes of the string. |
| Run the program | Let's click on Run button to run the program
Complier shows the following error, text string was not properly closed, expected a double quote “ ” to close the string. |
| Replace the quotes | Let's replace the quotes and run again.
press F5 key run the program. program runs without errors. |
| Slide Number 6
Runtime errors |
Run-time error occurs during the execution of a program.
It may crash the program when you run it. Runtime errors are commonly due to wrong input from the user. Compiler cannnot find these errors. For example:
|
| Next we will look at errors related to print command | |
| I already have a program in a text editor. | |
| reset
$C= ask "enter any number in celsius scale and click OK" message "$F is Fahrenheit" $F=(9/5*$C)+32 go 40,40 print "Value in Fahrenheit =" +" "+ $F+"F" |
Let me copy the program into Kturtle Editor
Please pause the tutorial and type the program into KTurtle editor
|
| Zoom text | Let me zoom into the program text.
It may possibly be a little blurred. |
| Highlight "Value in Kelvin ="+ $K + "K" and delete | Let's delete line after the keyword print "Value in Kelvin ="+ $K + "K" |
| Run the program | Let's click on Run button to run the program.
Complier does not shows any error. Here we get an error as the program runs. The print command was called with 0 but it needs 1 parameter. It is a runtime error. |
| Replace the deleted line | Let's replace the deleted line and Run again
program runs without runtime errors. |
| Next let's look at run time errors in loops. | |
| I already have a program in a text editor. | |
| #program to find multiples of 2
reset $x=0 message"In while loop, code inside the loop repeats till boolean evaluates false" while $x<20 { $x=$x+2 $x=$x*1 fontsize 15 forward 20 print $x } |
Let copy the program into Kturtle Editor
Please pause the tutorial and type the program into KTurtle editor
|
| Zoom text | Let me zoom into the program text.
It may possibly be a little blurred. |
| Highlight $x=$x+2 and $x=$x*1 | Let's delete the lines $x=$x+2 and $x=$x*1 |
| Run the program | Let's click on the Run button to run the program.
Complier does not show any error. We get a runtime error. Loop become an infinite loop of zeros. |
| Abort the process | I will click on Abort button to abort the process. |
| Undo the deleted line | Let's undo the deleted line and Run again
program runs properly as expected. |
| Let's now try another example for runtime error. | |
| I already have a program in a text editor. | |
| reset
$x=8 $r = 1 for $i = 1 to $x { $r = $r * $i forward 20 print $r } |
Let copy the program into KTurtle Editor.
Please pause the tutorial and type the program into KTurtle editor
|
| Zoom text | Let me zoom into the program text.
It may possibly be a little blurred. |
| Highlight $r = $r * $i and print $r | Let's delete the lines $r = $r * $i and print $r |
| Run the program | Let's click on the Run button to run the program.
Complier does not show any error. We get a runtime error. We see that only the Turtle has moved forward. “for” loop is not executed. |
| Undo the deleted line | Let's undo the deleted lines and Run again.
Program runs properly as expected. |
| With this we come to the end of this tutorial.
let us summarise. | |
| Slide Number 9
Summary |
In this tutorial we have learnt, errors such as
|
| Slide Number 10
Assignment |
As an assignment I would like you to find errors in the given programs- |
| Assignment 1 | reset
$x=3 $y=3 if $x==$y print"they are equal" else { print "they are not equal"} |
| Assignment 2 | program to find the nth term and sum of n terms in GP
reset $x=ask "enter value for x and click Ok" $y = ask "enter value for y and click Ok" $g =sqrt ($x*$y) print "Geometric mean is ="+ |
| Assignment 3 | reset
learn sum $x { {$r=0 for $i= 1 to $x{ return $r} } |
| 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 ] This is Madhuri Ganpathi from IIT Bombay Thank you for joining |
