KTurtle/C3/Common-Errors-in-KTurtle/English-timed

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Visual Cue Narration
00:01 Welcome to this tutorial on Common Errors in KTurtle.
00:07 In this tutorial, we will learn about
00:10 Syntax errors
00:12 Runtime errors and
00:14 Logical errors
00:17 To record this tutorial I am using,
00:20 Ubuntu Linux OS version 12.04.
00:25 KTurtle version. 0.8.1 beta.
00:31 We assume that you have basic working knowledge of KTurtle
00:36 If not, for relevant tutorials, please visit our website.

http://spoken-tutorial.org

00:42 Let's first define, What is an error ?
00:46 Error is a mistake in a program that produces an incorrect or unexpected result.
00:55 First I will explain about "Types of errors".
01:00 Syntax error is a violation of grammatical rules, of a programming language.
01:09 Compilation fails when a program has syntax errors.
01:15 Syntax errors are easy to find and fix.
01:22 For Example:
01:23 Unmatched parentheses, square and curly braces.
01:29 Use of variable that has not been declared.
01:34 Missing quotes in strings.
01:38 Let's open a new KTurtle Application.
01:42 Click on Dash home. In the Search bar, type KTurtle.
01:48 Click on the KTurtle icon.
01:51 Let's begin the tutorial with some types of syntax errors.
01:58 I already have a program in a text editor.
02:02 To explain the error in the program, I will comment part of the code.
02:09 Here, I will comment the line
02:11 $a=ask within double quotes "enter any number and click Ok"
02:19 I will use hash(#) sign to comment the line.
02:23 I will copy the program from text editor and paste it into Kturtle's Editor.
02:31 Pause the tutorial here and type the program into your KTurtle editor
02:37 Resume the tutorial after typing the program.
02:42 Let's click on Run button to run the program
02:47 Complier shows the following error,
02:50 variable "$a" was used without first being assigned to a value.
02:57 Here the error is in line number 4.
03:02 This is a syntax error. It occured, as the variable 'a' was not declared.
03:10 So I will go to line number 2, remove the comment.
03:14 I will copy the program from text Editor and paste it into KTurtle's editor.
03:23 Let's click on Run button to run the program
03:27 Enter 6 for a value and click OK
03:31 Program runs without errors.
03:35 I will clear the current program from KTurtle editor.
03:38 Type clear command and Run to clean the canvas.
03:43 let's next look at another error.
03:46 I already have a program in a text editor.
03:50 Here the value of "pi" is predefined in KTurtle.
03:54 Let's delete the "$" sign in the program.
03:58 I will copy the program from text editor and paste it into Kturtle's Editor
04:05 Pause the tutorial here and type the program into your KTurtle editor


04:11 Resume the tutorial after typing the program.
04:16 Let's Click on Run button to run the program.
04:19 Complier shows the following error,
04:22 you cannot put “=” here
04:26 This error is in line number 2.
04:30 This is a syntax error it occured, as there is no container of variable.
04:37 Let's go back to the program replace the $ sign.
04:41 I will copy the program from text editor and paste it into KTurtle's Editor
04:49 let's click on Run button to run the program.
04:53 Enter 45 for angle value and click OK
04:57 Program runs without errors.
05:00 Let's remove one of the quotes of the string.
05:05 I will Copy the program from text editor and paste it into KTurtle's Editor
05:12 Click on Run button to run the program
05:15 Complier shows the following error,
05:18 Text string was not properly closed, expected a double quote “ ” to close the string.
05:25 Here the error is in line number 2.
05:29 I will go back to line number 2 and replace the quotes.
05:34 I will copy the program from text editor and paste it into Kturtle's Editor
05:41 Click on Run button to run the program
05:44 Enter 45 for angle value and click OK.
05:49 Program runs without errors.
05:52 This way you can find the line at which error has occured, and also correct it.
05:59 Let's now learn about runtime errors.
06:04 Run-time error occurs during the execution of a program.
06:10 It may crash the program when you run it.
06:15 Runtime errors are commonly due to wrong input from the user.
06:23 Compiler cannnot find these errors.
06:27 For example:
06:29 Trying to divide by a variable that contains no value.
06:3 Run a loop without a terminating condition or increment value.
06:43 I will clear the current program from the editor.
06:47 Type clear command and Run to clean the canvas.
06:52 I already have a program in a text editor.
06:56 This program divides two numbers.
07:00 'a' is dividend and 'r' is divisor.
07:04 I will copy the program from text editor and paste it into KTurtle's Editor.
07:11 Pause the tutorial and type the program into your KTurtle editor
07:16 Resume the tutorial after typing the program.
07:20 Let us click on Run button to run the program.
07:24 let's enter 5 for 'a' and click OK
07:29 enter 0 for 'r' and click OK
07:33 Here we get a runtime error ,
07:36 “you tried to divide by zero”
07:39 This error is in line number 4.
07:43 This error occurs as we cannot divide a number with zero.
07:49 Let us run again.
07:51 Enter 5 for a and click OK
07:54 enter 2 for 'r' and click OK
07:58 Program without errors.
08:01 I will clear the current program from KTurtle editor.
08:05 Type clear command and Run to clean the canvas.
08:10 Next we will learn about logical errors.
08:14 Logical error is a mistake in a program's source code that results in incorrect or unexpected behavior.
08:26 For example,
08:28 Assigning a value to the wrong variable.
08:32 Multiplying two numbers instead of adding.
08:36 I already have a program in a text editor.
08:39 I will copy the program from text editor and paste it into Kturtle's Editor
08:47 Pause the tutorial here and type the program into your KTurtle editor
08:52 Resume the tutorial after typing the program.
08:57 Now click on the Run button to run the program.
09:01 A dialog box pops-up, let's click OK.
09:05 Loop goes into an infinite loop.
09:08 We see that “while” loop prints numbers from 31 and is still printing.
09:15 This is a logical error.
09:18 In the “while” condition x is greater than 20,
09:23 but the variable x is always greater than 20
09:28 So, the loop never terminates.
09:31 I will click on Abort button to abort the process.
09:36 Let's change $x=$x+1 to $x=$x-1.
09:44 I will copy the program from text editor and paste it into KTurtle's editor.
09:51 Let's click on Run button to run the program.
09:55 A dialog box pop-up. Let us click OK.
09:59 Loop terminates after printing the values from 29 to 20.
10:05 With this we come to the end of this tutorial.
10:10 Let us summarise.
10:12 In this tutorial we have learnt, errors and types of errors such as
10:18 Use of variable that has not been declared.
10:23 Missing quotes in strings.
10:27 Runtime errors and
10:30 Logical errors
10:3 As an assignment I would like you to find errors in the given programs
10:46 Watch the video available at this URl: http://spoken-tutorial.org/What is a Spoken Tutorial
10:50 It summarises the Spoken Tutorial project
10:54 If you do not have good bandwidth, you can download and watch it
10:59 The Spoken Tutorial Project Team :
11:01 Conducts workshops using spoken tutorials
11:05 Gives certificates to those who pass an online test
11:09 For more details, please write to contact@spoken-tutorial.org
11: 17 Spoken Tutorial Project is a part of the Talk to a Teacher project
11:23 It is supported by the National Mission on Education through ICT, MHRD, Government of India
11:31 More information on this Mission is available at this link http://spoken-tutorial.org/NMEICT-Intro ]
11:37 This is Madhuri Ganpathi from IIT Bombay.Signing off
11:41 Thank you for joining
This is Madhuri Ganpathi from IIT Bombay signing off.

Thank you for joining

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