Difference between revisions of "C-and-C++/C2/Logical-Operators/English-timed"

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{| border=1
 
{| border=1
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|| ''Time'''
+
|| Time
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|| '''Narration'''
+
|| Narration
  
 
|-
 
|-
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| 00.02
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| 00:02
 
| Welcome to the spoken tutorial on '''Logical operators in C and C++.'''
 
| Welcome to the spoken tutorial on '''Logical operators in C and C++.'''
  
 
|-
 
|-
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| 00.08
+
| 00:08
 
|In this tutorial we will learn about:Logical operators like  Logical AND eg. expression1 && expression2
 
|In this tutorial we will learn about:Logical operators like  Logical AND eg. expression1 && expression2
  
 
|-
 
|-
−
| 00.16
+
| 00:16
 
| Logical OR  
 
| Logical OR  
  
Line 18: Line 18:
  
 
|-
 
|-
−
| 00.21
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| 00:21
 
|Logical NOT
 
|Logical NOT
  
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|-
 
|-
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|00.25
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|00:25
 
| We will do this with the help of examples.
 
| We will do this with the help of examples.
  
 
|-
 
|-
−
| 00.28  
+
| 00:28  
 
|  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  
  
 
|-
 
|-
−
|00.33
+
|00:33
 
|'''gcc''' and '''g++ Compiler '''version '''4.6.1 on''' '''Ubuntu.'''
 
|'''gcc''' and '''g++ Compiler '''version '''4.6.1 on''' '''Ubuntu.'''
  
 
|-
 
|-
−
| 00.39
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| 00:39
 
| Let us start with the introduction to the '''logical operators'''.
 
| Let us start with the introduction to the '''logical operators'''.
  
 
|-
 
|-
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| 00.43
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| 00:43
 
|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
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| 00:48
 
|non zero means true
 
|non zero means true
  
 
|-
 
|-
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| 00.50
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| 00:50
 
|And  zero means false
 
|And  zero means false
  
  
 
|-
 
|-
−
| 00.53
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| 00:53
 
|Expressions using logical operators return 1 for '''true''' and 0 for '''false'''.
 
|Expressions using logical operators return 1 for '''true''' and 0 for '''false'''.
  
 
|-
 
|-
−
|  00.58
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|  00:58
 
|  Now I'll explain the logical operators with the help of an example.
 
|  Now I'll explain the logical operators with the help of an example.
  
 
|-
 
|-
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|  01.03
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|  01:03
 
|  Here is the program for '''logical operators''' in '''C'''.
 
|  Here is the program for '''logical operators''' in '''C'''.
  
 
|-
 
|-
−
| 01.08
+
| 01:08
 
|  Inside the main block
 
|  Inside the main block
  
 
|-
 
|-
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| 01.10
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| 01:10
 
|This statement declares the variables '''a''','''b''' and '''c''' as integers.
 
|This statement declares the variables '''a''','''b''' and '''c''' as integers.
  
 
|-
 
|-
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| 01.16
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| 01:16
 
| The '''printf''' statement prompts the user to enter the values of '''a''','''b''' and '''c'''.
 
| The '''printf''' statement prompts the user to enter the values of '''a''','''b''' and '''c'''.
  
 
|-
 
|-
−
|01.21
+
|01:21
 
| The '''scanf''' statement takes input from the user for  variables '''a''', '''b''' and''' c'''.
 
| The '''scanf''' statement takes input from the user for  variables '''a''', '''b''' and''' c'''.
  
 
|-
 
|-
−
| 01.28
+
| 01:28
 
|| Here, We are comparing the values of '''a''' with '''b''' and '''c''' to find the greatest.
 
|| Here, We are comparing the values of '''a''' with '''b''' and '''c''' to find the greatest.
  
 
|-
 
|-
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| 01.33
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| 01:33
 
|To compare simultaneously, we use the '''logical''' '''AND '''operator.
 
|To compare simultaneously, we use the '''logical''' '''AND '''operator.
  
 
|-
 
|-
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| 01.38
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| 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.
  
 
|-
 
|-
−
| 01.43
+
| 01:43
 
|The expression is not evaluated further on encountering a false condition.
 
|The expression is not evaluated further on encountering a false condition.
  
 
|-
 
|-
−
| 01.49
+
| 01:49
 
|So, the expression '''(a>c) '''is evaluated only if '''(a>b)''' is true.
 
|So, the expression '''(a>c) '''is evaluated only if '''(a>b)''' is true.
  
 
|-
 
|-
−
| 01.56
+
| 01:56
 
|If a is less than b, then the expression won't be evaluated further.
 
|If a is less than b, then the expression won't be evaluated further.
  
 
|-
 
|-
−
| 02.02
+
| 02:02
 
|This statement is  evaluated if the previous condition is true.  
 
|This statement is  evaluated if the previous condition is true.  
  
 
|-
 
|-
−
| 02.07
+
| 02:07
 
| Next '''(b>c) '''is evaluated.
 
| Next '''(b>c) '''is evaluated.
  
 
|-
 
|-
−
|02.10
+
|02:10
 
|  If the condition is true, then '''b is greatest''' is displayed on the screen.
 
|  If the condition is true, then '''b is greatest''' is displayed on the screen.
  
 
|-
 
|-
−
|  02.16
+
|  02:16
 
|  Otherwise '''c is greatest '''is displayed on the screen.  
 
|  Otherwise '''c is greatest '''is displayed on the screen.  
  
 
|-
 
|-
−
| 02.21
+
| 02:21
 
| We now come to the '''logical OR '''operator.
 
| We now come to the '''logical OR '''operator.
  
 
|-
 
|-
−
| 02.24
+
| 02:24
 
|Here, any one of the conditions has to be true for '''logical OR '''to return a true value.
 
|Here, any one of the conditions has to be true for '''logical OR '''to return a true value.
  
 
|-
 
|-
−
| 02.30
+
| 02:30
 
|The expression is not evaluated further on encountering a true condition.
 
|The expression is not evaluated further on encountering a true condition.
  
 
|-
 
|-
−
| 02.35
+
| 02:35
 
|So, if '''a''' == zero, then the remaining two expressions won't be evaluated.
 
|So, if '''a''' == zero, then the remaining two expressions won't be evaluated.
  
 
|-
 
|-
−
| 02.43
+
| 02:43
 
| This '''printf''' statement is executed if either of '''a''', '''b''' or '''c''' is 0.
 
| This '''printf''' statement is executed if either of '''a''', '''b''' or '''c''' is 0.
  
 
|-
 
|-
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| 02.49
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| 02:49
 
|  Coming to the end of the program. '''return 0''' and ending curly bracket.
 
|  Coming to the end of the program. '''return 0''' and ending curly bracket.
  
 
|-
 
|-
−
|  02.54
+
|  02:54
 
| Now save the program.
 
| Now save the program.
  
 
|-
 
|-
−
| 02.57
+
| 02:57
 
|'''Save''' it with extension '''.c'''
 
|'''Save''' it with extension '''.c'''
  
 
|-
 
|-
−
| 03.00
+
| 03:00
 
|I have saved my file as '''logical.c'''
 
|I have saved my file as '''logical.c'''
  
 
|-
 
|-
−
| 03.03
+
| 03:03
 
|  Open the terminal by pressing '''Ctrl, Alt and T '''keys simulataneously.
 
|  Open the terminal by pressing '''Ctrl, Alt and T '''keys simulataneously.
  
 
|-
 
|-
−
| 03.08
+
| 03:08
 
|  To compile the code type '''gcc space logical dot c space minus o space  log''' Press enter
 
|  To compile the code type '''gcc space logical dot c space minus o space  log''' Press enter
  
 
|-
 
|-
−
| 03.23
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| 03:23
 
|To  execute  type '''./log'''
 
|To  execute  type '''./log'''
  
 
|-
 
|-
−
| 03.27
+
| 03:27
 
|Press '''Enter.'''
 
|Press '''Enter.'''
  
  
 
|-
 
|-
−
| 03.29
+
| 03:29
 
|I will enter the values as,  
 
|I will enter the values as,  
  
Line 184: Line 184:
  
 
|-
 
|-
−
| 03.39
+
| 03:39
 
|The output is displayed as,
 
|The output is displayed as,
  
 
|-
 
|-
−
| 03.42
+
| 03:42
 
|c is greatest.  
 
|c is greatest.  
  
 
|-
 
|-
−
| 03.45
+
| 03:45
 
|The product of a, b and c is zero.
 
|The product of a, b and c is zero.
  
 
|-
 
|-
−
| 03.50
+
| 03:50
 
|You should try executing this program with different sets of inputs.
 
|You should try executing this program with different sets of inputs.
  
 
|-
 
|-
−
|03.55
+
|03:55
 
| Now Let's write the same program in C++
 
| Now Let's write the same program in C++
  
 
|-
 
|-
−
|  03.59
+
|  03:59
 
| I have already made the program and will take you through it.
 
| I have already made the program and will take you through it.
  
 
|-
 
|-
−
| 04.03
+
| 04:03
 
|Here is the code in '''C++'''.
 
|Here is the code in '''C++'''.
  
 
|-
 
|-
−
| 04.06
+
| 04:06
 
| | Now to make the same program in C++, we make a few changes.
 
| | Now to make the same program in C++, we make a few changes.
  
 
|-
 
|-
−
| 04.11
+
| 04:11
 
|There's a change in the header file.
 
|There's a change in the header file.
  
 
|-
 
|-
−
| 04.14
+
| 04:14
 
|Using statement has been used.
 
|Using statement has been used.
  
 
|-
 
|-
−
| 04.18
+
| 04:18
 
|Also there is a difference in output and input statements.
 
|Also there is a difference in output and input statements.
  
 
|-
 
|-
−
| 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.
  
  
 
|-
 
|-
−
| 04.25
+
| 04:25
 
|  Click on '''Save'''.
 
|  Click on '''Save'''.
  
 
|-
 
|-
−
| 04.27
+
| 04:27
 
| Make sure the file is saved with extension '''.cpp'''
 
| Make sure the file is saved with extension '''.cpp'''
  
 
|-  
 
|-  
−
|  04.31
+
|  04:31
 
|  Open the terminal by pressing '''Ctrl, Alt and T '''keys simulataneously.
 
|  Open the terminal by pressing '''Ctrl, Alt and T '''keys simulataneously.
  
 
|-
 
|-
−
|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
  
 
|-
 
|-
−
| 04.49
+
| 04:49
 
|to execute  type '''./log1'''
 
|to execute  type '''./log1'''
  
 
|-
 
|-
−
| 04.53
+
| 04:53
 
|press '''Enter.'''
 
|press '''Enter.'''
  
  
 
|-
 
|-
−
| 04.56
+
| 04:56
 
|I will enter the values as
 
|I will enter the values as
  
Line 268: Line 268:
  
 
|-
 
|-
−
| 05.02
+
| 05:02
 
|So we see the output is similar to the C program.
 
|So we see the output is similar to the C program.
  
 
|-
 
|-
−
| 05.05
+
| 05:05
 
|You should try executing the program with different sets of inputs too.
 
|You should try executing the program with different sets of inputs too.
  
 
|-
 
|-
−
|05.10  
+
|05:10  
 
| Now let us see an error which we can come across.
 
| Now let us see an error which we can come across.
  
 
|-
 
|-
−
| 05.12
+
| 05:12
 
|Let's switch to the editor.
 
|Let's switch to the editor.
  
 
|-
 
|-
−
|  05.16
+
|  05:16
 
|  Suppose here we forgot the brackets.
 
|  Suppose here we forgot the brackets.
  
 
|-
 
|-
−
| 05.20
+
| 05:20
 
|Delete this and this.
 
|Delete this and this.
  
 
|-
 
|-
−
|  05.26
+
|  05:26
 
| Let see what will happen, Save the program.
 
| Let see what will happen, Save the program.
  
 
|-
 
|-
−
| 05.30
+
| 05:30
 
|Come back to the terminal
 
|Come back to the terminal
  
 
|-
 
|-
−
| 05.32
+
| 05:32
 
|Compile and execute as before
 
|Compile and execute as before
  
 
|-
 
|-
−
| 05.38
+
| 05:38
 
|  We see the error:
 
|  We see the error:
  
 
|-
 
|-
−
| 05.41
+
| 05:41
 
|Expected identifier before '(' token.
 
|Expected identifier before '(' token.
  
 
|-
 
|-
−
|  05.45
+
|  05:45
 
|  This is because we have two different expressions here
 
|  This is because we have two different expressions here
  
 
|-
 
|-
−
| 05.48
+
| 05:48
 
|We have to evaluate them as one expression using AND operator.
 
|We have to evaluate them as one expression using AND operator.
  
 
|-
 
|-
−
| 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
  
 
|-
 
|-
−
|  05.57
+
|  05:57
 
|  Let us insert the brackets here and here.  
 
|  Let us insert the brackets here and here.  
  
 
|-
 
|-
−
| 06.04
+
| 06:04
 
|Click on '''Save'''
 
|Click on '''Save'''
  
 
|-
 
|-
−
| 06.06
+
| 06:06
 
|Come back to the terminal.
 
|Come back to the terminal.
  
 
|-
 
|-
−
|  06.09
+
|  06:09
 
| Compile and execute as before
 
| Compile and execute as before
  
 
|-
 
|-
−
| 06.14
+
| 06:14
 
|So it is working now.
 
|So it is working now.
  
 
|-
 
|-
−
| 06.22
+
| 06:22
 
|Let us now summarize the tutorial.
 
|Let us now summarize the tutorial.
  
 
|-
 
|-
−
| 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)) '''
  
 
   
 
   
 
|-
 
|-
−
| 06.32
+
| 06:32
 
|Logical OR
 
|Logical OR
  
Line 360: Line 360:
  
 
|-
 
|-
−
| 06.39
+
| 06:39
 
|Assignment
 
|Assignment
  
 
|-
 
|-
−
| 06.41
+
| 06:41
 
|Write a program that takes two numbers as input from the user.
 
|Write a program that takes two numbers as input from the user.
  
 
|-
 
|-
−
| 06.44
+
| 06:44
 
|Check whether the two numbers are equal or not using '''NOT''' operator. Hint: '''(a != b)'''
 
|Check whether the two numbers are equal or not using '''NOT''' operator. Hint: '''(a != b)'''
  
 
|-
 
|-
−
| 06.54
+
| 06:54
 
|  Watch the video available at the following link  
 
|  Watch the video available at the following link  
  
 
|-
 
|-
−
| 06.57
+
| 06:57
 
|It summarises the Spoken Tutorial project  
 
|It summarises the Spoken Tutorial project  
  
 
|-
 
|-
−
| 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  
  
Line 386: Line 386:
  
 
|-
 
|-
−
|  07.03
+
|  07:03
 
| The Spoken Tutorial Project Team * Conducts workshops using spoken tutorials  
 
| The Spoken Tutorial Project Team * Conducts workshops using spoken tutorials  
  
 
|-
 
|-
−
| 07.07
+
| 07:07
 
| Gives certificates for those who pass an online test  
 
| Gives certificates for those who pass an online test  
  
 
|-
 
|-
−
| 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  
  
 
|-
 
|-
−
| 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  
 
|-
 
|-
−
| 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  
  
 
|-
 
|-
−
| 07.27
+
| 07:27
 
| More information on this Mission is available at  
 
| More information on this Mission is available at  
  
 
|-
 
|-
−
| 07.30
+
| 07:30
 
| spoken hyphen tutorial dot org slash NMEICT hyphen Intro  
 
| spoken hyphen tutorial dot org slash NMEICT hyphen Intro  
  
Line 415: Line 415:
  
 
|-
 
|-
−
|  07.37
+
|  07:37
 
|  This is Ritwik Joshi from IIT Bombay.  
 
|  This is Ritwik Joshi from IIT Bombay.  
  

Revision as of 12:52, 23 June 2014

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 eg. 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
03:00 I have saved my file as logical.c
03:03 Open the terminal by pressing Ctrl, Alt and T keys simulataneously.
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
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
04:31 Open the terminal by pressing Ctrl, Alt and T keys simulataneously.
04:36 To compile the program type g++ logical.cpp space minus o space log1. Press Enter
04:49 to execute type ./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 summarises 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.

Contributors and Content Editors

Ashwini, PoojaMoolya, Pratik kamble, Sandhya.np14

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