Difference between revisions of "C-and-C++/C2/Logical-Operators/English-timed"
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− | |In this tutorial we will learn about:Logical operators like Logical AND | + | |In this tutorial we will learn about: Logical operators like Logical AND e.g. expression1 && expression2 |
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− | | To record this tutorial, I am using:'''Ubuntu 11.10''' as the operating system | + | | To record this tutorial, I am using: '''Ubuntu 11.10''' as the operating system, |
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|00:33 | |00:33 | ||
− | |'''gcc''' and '''g++ Compiler '''version '''4.6.1 | + | |'''gcc''' and '''g++ Compiler '''version '''4.6.1 '''on '''Ubuntu.''' |
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− | |In '''C '''and '''C++,''' '''true''' is any value other than 0. | + | |In '''C '''and '''C++,''' '''true''' is any value other than '''0'''. |
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| 00:48 | | 00:48 | ||
− | | | + | |Non zero means true, |
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| 00:50 | | 00:50 | ||
− | | | + | |and zero means false. |
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− | | Inside the main block | + | | Inside the main block, |
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| 01:10 | | 01:10 | ||
− | | | + | |this statement declares the variables '''a''','''b''' and '''c''' as integers. |
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| 01:38 | | 01:38 | ||
− | |Here, all of the conditions have to be true for '''logical AND '''to return a true value. | + | |Here, all of the conditions have to be true for '''logical AND '''to return a '''true''' value. |
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− | |This statement is | + | |This statement is evaluated if the previous condition is true. |
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− | |'''Save''' it with extension '''.c''' | + | |'''Save''' it with extension '''.c''' (dot c). |
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| 03:00 | | 03:00 | ||
− | |I have saved my file as '''logical.c''' | + | |I have saved my file as '''logical.c'''. |
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| 03:03 | | 03:03 | ||
− | | Open the terminal by pressing '''Ctrl, Alt and T '''keys | + | | Open the terminal by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously. |
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| 03:08 | | 03:08 | ||
− | | To compile the code type '''gcc space logical dot c space minus o space log''' Press | + | | To compile the code type '''gcc space logical dot c space minus o space log'''. Press Enter |
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| 03:23 | | 03:23 | ||
− | |To execute type '''./log''' | + | |To execute, type '''./log''' (dot slash log) |
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| 03:27 | | 03:27 | ||
|Press '''Enter.''' | |Press '''Enter.''' | ||
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| 03:42 | | 03:42 | ||
− | |c is greatest. | + | |'''c is greatest'''. |
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|03:55 | |03:55 | ||
− | | Now Let's write the same program in C++ | + | | Now Let's write the same program in C++. |
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| 04:14 | | 04:14 | ||
− | | | + | |'''using''' statement has been used. |
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| 04:21 | | 04:21 | ||
|The operators behave in the same way as they did in C. | |The operators behave in the same way as they did in C. | ||
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| 04:27 | | 04:27 | ||
− | | Make sure the file is saved with extension '''.cpp''' | + | | Make sure the file is saved with extension '''.cpp''' (dot cpp). |
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| 04:31 | | 04:31 | ||
− | | Open the terminal by pressing '''Ctrl, Alt and T '''keys | + | | Open the terminal by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously. |
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|04:36 | |04:36 | ||
− | |To compile the program type '''g++ logical.cpp space minus o space log1'''. Press Enter | + | |To compile the program type '''g++ logical.cpp space minus o space log1'''. Press Enter. |
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| 04:49 | | 04:49 | ||
− | | | + | |To execute, type '''./log1''' (dot slash log1). |
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| 04:53 | | 04:53 | ||
|press '''Enter.''' | |press '''Enter.''' | ||
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| 05:30 | | 05:30 | ||
− | |Come back to the terminal | + | |Come back to the terminal. |
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| 05:32 | | 05:32 | ||
− | |Compile and execute as before | + | |Compile and execute as before. |
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| 05:41 | | 05:41 | ||
− | |Expected identifier before '(' token. | + | |'''Expected identifier before '(' token'''. |
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| 05:45 | | 05:45 | ||
− | | This is because we have two different expressions here | + | | This is because we have two different expressions here. |
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| 05:53 | | 05:53 | ||
− | | Now let us go back to our program and fix the error | + | | Now let us go back to our program and fix the error. |
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| 06:04 | | 06:04 | ||
− | |Click on '''Save''' | + | |Click on '''Save'''. |
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| 06:09 | | 06:09 | ||
− | | Compile and execute as before | + | | Compile and execute as before. |
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| 06:24 | | 06:24 | ||
| In this tutorial we learnt about Logical AND eg. '''((a > b) && (a > c)) ''' | | In this tutorial we learnt about Logical AND eg. '''((a > b) && (a > c)) ''' | ||
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eg. '''(a == 0 || b == 0 || c == 0) ''' | eg. '''(a == 0 || b == 0 || c == 0) ''' | ||
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| 06:39 | | 06:39 | ||
− | |Assignment | + | |Assignment, |
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| 06:54 | | 06:54 | ||
− | | Watch the video available at the following link | + | | Watch the video available at the following link. |
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| 06:57 | | 06:57 | ||
− | |It | + | |It summaries the Spoken Tutorial project. |
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| 06:59 | | 06:59 | ||
− | |If you do not have good bandwidth, you can download and watch it | + | |If you do not have good bandwidth, you can download and watch it. |
− | + | ||
− | + | ||
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| 07:03 | | 07:03 | ||
− | | The Spoken Tutorial Project Team | + | | The Spoken Tutorial Project Team : Conducts workshops using spoken tutorials. |
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| 07:07 | | 07:07 | ||
− | | Gives certificates for those who pass an online test | + | | Gives certificates for those who pass an online test. |
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| 07:11 | | 07:11 | ||
− | | For more details, please write to contact at spoken hyphen tutorial dot org | + | | For more details, please write to contact at spoken hyphen tutorial dot org. |
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| 07:18 | | 07:18 | ||
− | | Spoken Tutorial Project is a part of the Talk to a Teacher project | + | | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
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| 07:21 | | 07:21 | ||
− | |It is supported by the National Mission on Education through ICT, MHRD, Government of India | + | |It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
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| 07:30 | | 07:30 | ||
− | | spoken hyphen tutorial dot org slash NMEICT hyphen Intro | + | | spoken hyphen tutorial dot org slash NMEICT hyphen Intro. |
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Revision as of 14:38, 5 February 2015
Time | Narration |
00:02 | Welcome to the spoken tutorial on Logical operators in C and C++. |
00:08 | In this tutorial we will learn about: Logical operators like Logical AND e.g. expression1 && expression2 |
00:16 | Logical OR
eg. expression1 or expression2 |
00:21 | Logical NOT
eg. not (Expression1) |
00:25 | We will do this with the help of examples. |
00:28 | To record this tutorial, I am using: Ubuntu 11.10 as the operating system, |
00:33 | gcc and g++ Compiler version 4.6.1 on Ubuntu. |
00:39 | Let us start with the introduction to the logical operators. |
00:43 | In C and C++, true is any value other than 0. |
00:48 | Non zero means true, |
00:50 | and zero means false. |
00:53 | Expressions using logical operators return 1 for true and 0 for false. |
00:58 | Now I'll explain the logical operators with the help of an example. |
01:03 | Here is the program for logical operators in C. |
01:08 | Inside the main block, |
01:10 | this statement declares the variables a,b and c as integers. |
01:16 | The printf statement prompts the user to enter the values of a,b and c. |
01:21 | The scanf statement takes input from the user for variables a, b and c. |
01:28 | Here, We are comparing the values of a with b and c to find the greatest. |
01:33 | To compare simultaneously, we use the logical AND operator. |
01:38 | Here, all of the conditions have to be true for logical AND to return a true value. |
01:43 | The expression is not evaluated further on encountering a false condition. |
01:49 | So, the expression (a>c) is evaluated only if (a>b) is true. |
01:56 | If a is less than b, then the expression won't be evaluated further. |
02:02 | This statement is evaluated if the previous condition is true. |
02:07 | Next (b>c) is evaluated. |
02:10 | If the condition is true, then b is greatest is displayed on the screen. |
02:16 | Otherwise c is greatest is displayed on the screen. |
02:21 | We now come to the logical OR operator. |
02:24 | Here, any one of the conditions has to be true for logical OR to return a true value. |
02:30 | The expression is not evaluated further on encountering a true condition. |
02:35 | So, if a == zero, then the remaining two expressions won't be evaluated. |
02:43 | This printf statement is executed if either of a, b or c is 0. |
02:49 | Coming to the end of the program. return 0 and ending curly bracket. |
02:54 | Now save the program. |
02:57 | Save it with extension .c (dot c). |
03:00 | I have saved my file as logical.c. |
03:03 | Open the terminal by pressing Ctrl, Alt and T keys simultaneously. |
03:08 | To compile the code type gcc space logical dot c space minus o space log. Press Enter |
03:23 | To execute, type ./log (dot slash log) |
03:27 | Press Enter. |
03:29 | I will enter the values as,
0 34 567 |
03:39 | The output is displayed as, |
03:42 | c is greatest. |
03:45 | The product of a, b and c is zero. |
03:50 | You should try executing this program with different sets of inputs. |
03:55 | Now Let's write the same program in C++. |
03:59 | I have already made the program and will take you through it. |
04:03 | Here is the code in C++. |
04:06 | Now to make the same program in C++, we make a few changes. |
04:11 | There's a change in the header file. |
04:14 | using statement has been used. |
04:18 | Also there is a difference in output and input statements. |
04:21 | The operators behave in the same way as they did in C. |
04:25 | Click on Save. |
04:27 | Make sure the file is saved with extension .cpp (dot cpp). |
04:31 | Open the terminal by pressing Ctrl, Alt and T keys simultaneously. |
04:36 | To compile the program type g++ logical.cpp space minus o space log1. Press Enter. |
04:49 | To execute, type ./log1 (dot slash log1). |
04:53 | press Enter. |
04:56 | I will enter the values as
0 34 567 |
05:02 | So we see the output is similar to the C program. |
05:05 | You should try executing the program with different sets of inputs too. |
05:10 | Now let us see an error which we can come across. |
05:12 | Let's switch to the editor. |
05:16 | Suppose here we forgot the brackets. |
05:20 | Delete this and this. |
05:26 | Let see what will happen, Save the program. |
05:30 | Come back to the terminal. |
05:32 | Compile and execute as before. |
05:38 | We see the error: |
05:41 | Expected identifier before '(' token. |
05:45 | This is because we have two different expressions here. |
05:48 | We have to evaluate them as one expression using AND operator. |
05:53 | Now let us go back to our program and fix the error. |
05:57 | Let us insert the brackets here and here. |
06:04 | Click on Save. |
06:06 | Come back to the terminal. |
06:09 | Compile and execute as before. |
06:14 | So it is working now. |
06:22 | Let us now summarize the tutorial. |
06:24 | In this tutorial we learnt about Logical AND eg. ((a > b) && (a > c)) |
06:32 | Logical OR
eg. (a == 0 || b == 0 || c == 0) |
06:39 | Assignment, |
06:41 | Write a program that takes two numbers as input from the user. |
06:44 | Check whether the two numbers are equal or not using NOT operator. Hint: (a != b) |
06:54 | Watch the video available at the following link. |
06:57 | It summaries the Spoken Tutorial project. |
06:59 | If you do not have good bandwidth, you can download and watch it. |
07:03 | The Spoken Tutorial Project Team : Conducts workshops using spoken tutorials. |
07:07 | Gives certificates for those who pass an online test. |
07:11 | For more details, please write to contact at spoken hyphen tutorial dot org. |
07:18 | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
07:21 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
07:27 | More information on this Mission is available at |
07:30 | spoken hyphen tutorial dot org slash NMEICT hyphen Intro. |
07:37 | This is Ritwik Joshi from IIT Bombay.
Thank you for joining. |