Difference between revisions of "KTurtle/C3/Common-Errors-in-KTurtle/English-timed"
From Script | Spoken-Tutorial
| Line 515: | Line 515: | ||
||11:41 | ||11:41 | ||
||Thank you for joining | ||Thank you for joining | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
Revision as of 10:57, 1 August 2013
| 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. |
| 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 |
Contributors and Content Editors
Devraj, Kavita salve, PoojaMoolya, Pratik kamble, Sakinashaikh, Sandhya.np14, Sneha
