Difference between revisions of "KTurtle/C3/Common-Errors-in-KTurtle/English"

From Script | Spoken-Tutorial
Jump to: navigation, search
Line 23: Line 23:
 
||To record this tutorial I am using,
 
||To record this tutorial I am using,
  
Ubuntu Linux OS version. 12.04.  
+
Ubuntu Linux OS version 12.04.  
  
 
KTurtle version. 0.8.1 beta.
 
KTurtle version. 0.8.1 beta.
Line 107: Line 107:
  
 
'''spritehide'''
 
'''spritehide'''
||I will Copy the program from text editor and paste it into '''Kturtle''' Editor.
+
||I will Copy the program from text editor and paste it into '''Kturtle's''' Editor.
  
 
Please pause the tutorial here and type the program your into '''KTurtle''' editor  
 
Please pause the tutorial here and type the program your into '''KTurtle''' editor  
Line 114: Line 114:
 
|-
 
|-
 
||'''Run the program'''
 
||'''Run the program'''
||Let's Click on Run button to run the program  
+
||Let's Click on '''Run''' button to run the program  
  
 
Complier shows the following error,
 
Complier shows the following error,
Line 138: Line 138:
  
 
'''spritehide'''
 
'''spritehide'''
|| I will copy the program from text Editor and paste it into KTurtle editor.
+
|| I will copy the program from text Editor and paste it into KTurtle's editor.
 
|-
 
|-
 
||'''Run the program'''
 
||'''Run the program'''
||Let's click on Run button to run the program  
+
||Let's click on '''Run''' button to run the program  
  
 
Enter 6 for any value and click OK
 
Enter 6 for any value and click OK
Line 177: Line 177:
  
 
'''spritehide'''
 
'''spritehide'''
||I will copy the program from text editor and paste it into ''' Kturtle''' Editor
+
||I will copy the program from text editor and paste it into ''' Kturtle's ''' Editor
  
 
Please pause the tutorial and type the program your into '''KTurtle''' editor  
 
Please pause the tutorial and type the program your into '''KTurtle''' editor  
Line 195: Line 195:
 
|-
 
|-
 
||'''Show error'''
 
||'''Show error'''
||This syntax error occured, as there is no container  of variables.
+
||This syntax error it occured, as there is no container  of variables.
 
|-
 
|-
 
||'''Replace $ sign'''  
 
||'''Replace $ sign'''  
Line 214: Line 214:
 
|-
 
|-
 
||'''Run the program'''
 
||'''Run the program'''
||Click on '''Run''' button to run the program.
+
||let's click on '''Run''' button to run the program.
  
 
Enter 45 for angle value and click OK
 
Enter 45 for angle value and click OK
Line 237: Line 237:
  
 
'''spritehide'''  
 
'''spritehide'''  
|| I will copy the program from text editor and paste it into '''KTurtle''' Editor  
+
|| Copy the program from text editor and paste it into '''KTurtle's ''' Editor  
 
|-
 
|-
 
||'''Run the program'''
 
||'''Run the program'''
Line 244: Line 244:
 
Complier shows the following error,
 
Complier shows the following error,
  
'''text string was not properly closed, expected a double quote “ ” to close the string.'''
+
'''Text string was not properly closed, expected a double quote “ ” to close the string.'''
 
|-
 
|-
 
||Highlight '''Line number 2'''
 
||Highlight '''Line number 2'''
||Here the error is in line number 2.  
+
||This error is in line number 2.  
 
|-
 
|-
 
||'''Replace the quotes'''  
 
||'''Replace the quotes'''  
Line 267: Line 267:
 
|-
 
|-
 
||'''Run the program'''
 
||'''Run the program'''
||Click on Run Button to  execute again.
+
||Let's run again
  
 
Enter 45 for angle value and click OK.
 
Enter 45 for angle value and click OK.
Line 273: Line 273:
 
Program runs without errors.  
 
Program runs without errors.  
  
This way you can find the line at which error has occured, and correct it.  
+
This way you can find the line at which error has occured, and also correct it.  
 
|-
 
|-
 
||
 
||
Line 290: Line 290:
  
 
For example:
 
For example:
* Trying to multiply or divide by a variable that contains no value.
+
* Trying to divide by a variable that contains no value.
  
 
* Run a loop without a terminating condition or increment value.
 
* Run a loop without a terminating condition or increment value.
Line 297: Line 297:
 
||I will clear the current program from the editor.
 
||I will clear the current program from the editor.
  
Type clear command and '''Run''' to clean the canvas.
+
Type '''clear''' command and '''Run''' to clean the canvas.
 
|-
 
|-
 
||Highlight the program
 
||Highlight the program
Line 316: Line 316:
 
'''print $d'''
 
'''print $d'''
 
||
 
||
I will copy the program into Kturtle Editor.  
+
I will copy the program from text editor and paste it into KTurtle's Editor.  
  
 
Pause the tutorial and type the program into your KTurtle editor  
 
Pause the tutorial and type the program into your KTurtle editor  
Line 323: Line 323:
 
|-
 
|-
 
||'''Run the program'''  
 
||'''Run the program'''  
||Let's click on the Run button to run the program.
+
||Let's click on the '''Run''' button to run the program.  
 
+
Complier does not show any error.  
+
  
 
Let's enter 5 for 'a' and click OK
 
Let's enter 5 for 'a' and click OK
Line 351: Line 349:
 
|-
 
|-
 
||'''“clear” command'''
 
||'''“clear” command'''
||I will clear the current program from the editor.
+
||I will clear the current program from '''KTurtle''' editor.
  
 
Type '''clear''' command and '''Run''' to clean the canvas.
 
Type '''clear''' command and '''Run''' to clean the canvas.
 
|-
 
|-
 
||
 
||
||Next we will learn about logical errors.
+
||Next we will learn about ''' logical errors'''.
 
|-
 
|-
 
||'''Logical errors'''  
 
||'''Logical errors'''  
Line 390: Line 388:
 
||I will copy the program from text editor and paste it into Kturtle's Editor  
 
||I will copy the program from text editor and paste it into Kturtle's Editor  
  
Pause the tutorial and type the program into your KTurtle editor  
+
Pause the tutorial here and type the program into your KTurtle editor  
  
 
Resume the tutorial after typing the program.  
 
Resume the tutorial after typing the program.  
Line 398: Line 396:
 
||Now click on the '''Run''' button to run the program.  
 
||Now click on the '''Run''' button to run the program.  
  
A dilog box pops-up let's click OK.
+
A dilog box pops-up, let's click OK.
  
 
Loop goes into an infinite loop.  
 
Loop goes into an infinite loop.  
Line 414: Line 412:
 
|-
 
|-
 
||'''Abort the process'''  
 
||'''Abort the process'''  
||I will click on Abort button to abort the process.  
+
||I will click on '''Abort''' button to abort the process.  
 
|-
 
|-
 
||Change '''$x=$x+1''' to '''$x=$x-1'''
 
||Change '''$x=$x+1''' to '''$x=$x-1'''
Line 438: Line 436:
 
|-  
 
|-  
 
||'''Run the program'''
 
||'''Run the program'''
||Click on the Run button to run the program.  
+
||Let's click on the '''Run''' button to run the program.  
  
A dilog box pop-up let's click OK.
+
A dilog box pop-up let's click OK.
  
 
Loop terminates after printing values from 29 to 20.  
 
Loop terminates after printing values from 29 to 20.  
Line 458: Line 456:
 
* Missing quotes in strings.
 
* Missing quotes in strings.
  
* Errors related to print command
+
* Runtime errors and
 
+
* Runtime errors
+
  
 
* Logical errors
 
* Logical errors

Revision as of 15:01, 18 February 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
  • Syntax errors
  • Runtime errors and
  • Logical errors
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

Slide Number 5

Definition of Error

Let's first define, What is an error ?

Error is a mistake in a program that produces an incorrect or unexpected result.

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:

  • Unmatched parentheses, square brackets and curly braces.
  • Use of variable that has not been declared.
  • Missing quotes in strings.
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. 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.
Comment code To explain the error in the program, I will comment part of the code.
Highlight

$a=ask "enter any number and click Ok"

Here, I will comment

$a=ask within double quotes "enter any number and click Ok"

Type # I will use hash(#) sign to comment the line.
reset

#$a=ask "enter any number and click ok"

print $a^3'

spritehide

I will Copy the program from text editor and paste it into Kturtle's Editor.

Please pause the tutorial here and type the program your into KTurtle editor

Resume the tutorial after typing the program.

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.

Highlight Line number 4 This error is in line number 4
Syntax error This is a syntax error. It occured, as the variable 'a' was not declared.
Highlight $a=ask "enter any number and click Ok"

Remove the comment

So I will go back to line number 2 remove the comment.
reset

$a=ask "enter a number and click ok"

print $a^3

spritehide

I will copy the program from text Editor and paste it into KTurtle's editor.
Run the program Let's click on Run button to run the program

Enter 6 for any value and click OK

Program runs without errors.

clear command I will clear the current program from the KTurtle editor.

Type clear command and Run to clean the canvas.

Next let's learn about another error.
I already have a program in a text editor.
Highlight

$radian=(pi/180)*$degree

Value of "pi" is predefined in KTurtle.
Highlight $ Let's delete the "$" sign in the program.
reset

degree=ask "enter an angle value and click OK"

$radian=(pi/180)*$degree

go 50,50

print "Value in radians is"+ " " +$radian

spritehide

I will copy the program from text editor and paste it into Kturtle's Editor

Please pause the tutorial and type the program your into KTurtle editor


Resume the tutorial after typing the program.

Run the program Let's Click on Run button to run the program.

Complier shows the following error,

you cannot put “=” here

Highlight Line number 2 This error is in line number 2.
Show error This syntax error it occured, as there is no container of variables.
Replace $ sign Let's go back to the program replace the $ sign.
reset

$degree=ask "enter an angle value and click OK"

$radian=(pi/180)*$degree

go 50,50

print "Value in radians is"+ " " +$radian

spritehide

I will copy the program from text editor and paste it into KTurtle's Editor
Run the program let's click on Run button to run the program.

Enter 45 for angle value and click OK

Program runs without errors.

Next let's look at another error.
Highlight "enter an angle value and click OK" Let's remove one of the quotes of the string.
reset

$degree=ask "enter an angle value and click OK

$radian=(pi/180)*$degree

go 50,50

print "Value in radians is"+ " " +$radian

spritehide

Copy the program from text editor and paste it into KTurtle's Editor
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.

Highlight Line number 2 This error is in line number 2.
Replace the quotes So I will go to line number 2 and replace the quotes.
reset

$degree=ask "enter an angle value and click OK"

$radian=(pi/180)*$degree

go 50,50

print "Value in radians is"+ " " +$radian

spritehide

I will copy the program from text editor and paste it into Kturtle Editor

Run the program Let's run again

Enter 45 for angle value and click OK.

Program runs without errors.

This way you can find the line at which error has occured, and also correct it.

Let's now learn about runtime 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:

  • Trying to divide by a variable that contains no value.
  • Run a loop without a terminating condition or increment value.
“clear” command' I will clear the current program from the editor.

Type clear command and Run to clean the canvas.

Highlight the program I already have a program in a text editor.

This program divides two numbers.

'a' is dividend and 'r' is divisor.

reset

$a=ask "enter a number for 'a' and click Ok"'

$r = ask "enter a number for 'r' and click OK"

$d=$a/$r

print $d

I will copy the program from text editor and paste it into KTurtle's Editor.

Pause the tutorial and type the program into your KTurtle editor

Resume the tutorial after typing the program.

Run the program Let's click on the Run button to run the program.

Let's enter 5 for 'a' and click OK

enter 0 for 'r' and click OK

Here we get a runtime error,

“ you tried to divide by zero”

Highlight Line number 4 This error is in line number 4.
Run time error This error occurs as we cannot divide a number with zero.
Run the program Let's run the program again.

Let's enter 5 for 'a' and click OK

enter 2 for 'r' and click OK

Program without errors.

“clear” command I will clear the current program from KTurtle editor.

Type clear command and Run to clean the canvas.

Next we will learn about logical errors.
Logical errors Logical error is a mistake in a program's source code that results in incorrect or unexpected behavior.

For example,

Assigning a value to the wrong variable.

Multiplying two numbers instead of adding.

I already have a program in a text editor.
reset

$x=30

message"In while loop, code inside the loop repeats till boolean

evaluates false"

while $x>20 {

$x=$x+1

fontsize 15

forward 20

print $x }

I will copy the program from text editor and paste it into Kturtle's Editor

Pause the tutorial here and type the program into your KTurtle editor

Resume the tutorial after typing the program.

Run the program Now click on the Run button to run the program.

A dilog box pops-up, let's click OK.

Loop goes into an infinite loop.

Highlight “ while” loop condition We see that “while” loop prints numbers from 31 and it is still printing.

This is a logical error.

In this “while” condition x is greater than 20,

but the variable x is always greater than 20

So the loop never terminates.

Abort the process I will click on Abort button to abort the process.
Change $x=$x+1 to $x=$x-1 Let's change $x=$x+1 to $x=$x-1.
reset

$x=30

message"In while loop, code inside the loop repeats till boolean evaluates false"

while $x>20 {

'$x=$x-1'

fontsize 15

forward 20

print $x }

Copy the program from text editor and paste it into KTurtle's editor.
Run the program Let's click on the Run button to run the program.

A dilog box pop-up let's click OK.

Loop terminates after printing values from 29 to 20.

With this we have come to the end of this tutorial.

Let us summarise.

Slide Number 9

Summary

In this tutorial we have learnt, errors and types of errors such as
  • Use of variable that has not been declared.
  • Missing quotes in strings.
  • Runtime errors and
  • Logical errors
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}

}

print

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

Contributors and Content Editors

Arya Ratish, Madhurig