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

Time	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	Run time 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:,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	$a=ask within double quotes "enter any number and click Ok".
02:19	I will use hash(#) sign to comment the line.
02:23	I will copy the program from text-editor and paste it into Kturtle's editor.
02:31	Pause the tutorial here and type the program into your KTurtle editor.
02:37	Resume the tutorial after typing the program.
02:42	Let's click on Run button to run the program.
02:47	Compiler shows the following error:
02:50	"variable '$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 occurred 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 '$' sign in the program.
03:58	I will copy the program from text editor and paste it into Kturtle's Editor.
04:05	Pause the tutorial here and type the program into your KTurtle editor.
04:11	Resume the tutorial after typing the program.
04:16	Let's click on Run button to run the program.
04:19	Complier shows the following error:
04:22	"You cannot put '=' here".
04:26	This error is in line number 2.
04:30	This is a syntax error. It occurred as there is no container of variable.
04:37	Let's go back to the program, replace the '$' 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 occurred and also correct it.
05:59	Let's now learn about run time 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 cannot find these errors.
06:27	For example:
06:29	Trying to divide by a variable that contains no value.
06:31	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 here 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 run time 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 runs 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 a 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 pops 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 summarize.
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.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 summarizes 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 :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.

Contributors and Content Editors

Devraj, Kavita salve, PoojaMoolya, Pratik kamble, Sakinashaikh, Sandhya.np14, Sneha