Nancyvarkey at 08:50, 23 March 2017

2017-03-23T08:50:30Z

Nancyvarkey: Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Scope of variables in C and C++'''. |- | 00:08 |In this tutorial we will learn..."

2015-04-10T11:06:02Z

Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Scope of variables in C and C++'''. |- | 00:08 |In this tutorial we will learn..."

New page

{| border=1
|| '''Time'''
|| '''Narration'''

|-
| 00:01
| Welcome to the spoken tutorial on '''Scope of variables in C and C++'''.

|-
| 00:08
|In this tutorial we will learn,

|-
| 00:11
|* What is the Scope of variable?

|-
| 00:13
|* What is a Global variable?

|-
| 00:16
|* What is a Local variable?

|-
| 00:19
|Few examples.

|-
| 00:22
|We will also see some common errors and their solutions.

|-
|00:27
| To record this tutorial, I am using

|-
| 00:30
|'''Ubuntu Operating System''' version 11.04, '''gcc''' and '''g++ Compiler''' version 4.6.1.

|-
| 00:41
| Let us start with the introduction to the scope of variables.

|-
| 00:47
|It is the region of code within which the variable can be accessed.

|-
| 00:54
|Depending on it's type and place of declaration it is divided into two categories:

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| 00:59
|Global Variable &

|-
| 01:02
|Local Variable.

|-
|01:05
| Now we will see an example.

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| 01:07
|I have already typed the program on the editor.

|-
| 01:10
|Let me open it.

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| 01:14
|Note that our file name is '''scope.c.'''

|-
| 01:19
|Let me explain the code now.

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| 01:23
|This is our '''header file.'''

|-
|01:26
|Here we have declared two global variables '''a and b.'''

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| 01:32
|And we have '''initialized''' them by assigning values as '''5 and 2.'''

|-
| 01:39
|A global variable is available to all functions in your program.

|-
| 01:44
|These are declared outside any functions, above main() function.

|-
| 01:51
|These have a '''global scope.'''

|-
| 01:53
|Here we have declared a '''function''' '''add '''without''' arguments.'''

|-
|01:59
|Here 'sum' is a local variable, it is declared inside the function '''add'''.

|-
| 02:07
|A local variable is available only to the function inside which it is declared.

|-
| 02:13
|These variables are declared inside a block.

|-
| 02:16
|These have '''local scope'''.

|-
| 02:19
|Then sum of a & b will be stored in the variable 'sum'. Here we print the sum.

|-
| 02:29
| This is our '''main()''' function.

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| 02:33
| The '''add''' function is called and then executed.

|-
| 02:38
| And this is our '''return''' statement.

|-
|02:40
| Now click on Save.

|-
| 02:43
| Let us execute the program.

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| 02:45
| | Please open the terminal window by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously on your keyboard.

|-
| 02:55
| To compile, type

|-
| 02:56
|'''gcc space scope.c space hyphen o space sco''' and press Enter.

|-
| 03:05
|To execute,

|-
| 03:06
|type '''./sco''' (dot slash sco), press Enter.

|-
| 03:10
| The output is displayed as

|-
| 03:13
|'''Sum of a and b is 7'''.

|-
| 03:16
| Now let us see how to execute the same program in C++.

|-
| 03:20
| Come back to our program. First press '''Shift, Ctrl''' & '''S''' keys simultaneously on your keyboard.

|-
| 03:31
|Now save the file with an extension '''.cpp ''' (dot cpp) and click on Save.

|-
| 03:41
| Let us change the header file as '''iostream'''.

|-
| 03:47
| Now include the '''using '''statement. Click on save .

|-
| 03:58
| The declaration of global variable and local variable is same in C++.

|-
| 04:03
|So, no need to change anything.

|-
| 04:07
| Now replace the '''printf '''statement with the '''cout''' statement.

|-
| 04:13
| Delete the '''format specifier''' and '\n'.

|-
| 04:17
|Now delete the comma.

|-
| 04:19
| Type two opening angle brackets.

|-
| 04:22
|Delete the closing bracket, again type two opening angle brackets.

|-
| 04:26
|And within the double quotes type backslash n. Now click on Save.

|-
| 04:35
|Let us execute the program.

|-
| 04:39
|Come back to our terminal.

|-
| 04:42
| To compile, type '''g++ space scope dot cpp space -o space sco1 '''

|-
| 04:52
| Here we have '''sco1''' because we don't want to overwrite output parameter '''sco''' for the file 'scope.c'.

|-
| 05:04
| Now press Enter.

|-
| 05:07
| To execute type '''./sco1''' and press Enter.

|-
|05:14
|The output is displayed as '''Sum of a and b is 7.'''

|-
| 05:19
| We can see that it is similar to our C code.

|-
| 05:27
|Now we will see some common errors which we can come across.

|-
| 05:31
|Come back to our program. Suppose here I will declare a variable '''a''' again.

|-
| 05:41
|Type '''int a ''' and a semicolon.

|-
| 05:45
| Click on Save. We have declared the variable 'a' above the main() function and after the '''add''' function.

|-
| 05:55
| Let us see what happens.

|-
| 05:57
|Come back to our terminal.

|-
|06:01
| Now compile as before.

|-
|06:05
|We see errors, '''redefinition of 'int a' ''' , ''' 'int a' previously defined here'''. Come back to our program.

|-
|06:18
|'''a''' is a global variable.

|-
|06:20
|It has a '''global scope.'''

|-
|06:22
|We cannot declare the variable twice as it is already declared globally.

|-
|06:27
|We can only declare '''variable a''' as a local variable .

|-
|06:34
|Let us fix the error.

|-
| 06:36
| Delete this .

|-
| 06:39
| Click on Save.

|-
| 06:41
| Let us execute again.

|-
|06:42
|Come back to our terminal.

|-
| 06:45
| Now compile as before, execute as before.

|-
| 06:49
| Yes, it is working.

|-
|06:52
|This brings us to the end of this tutorial.

|-
| 06:56
| Let us summarize.

|-
| 06:58
| In this tutorial we learnt ,

|-
| 07:00
| Scope of variable,

|-
| 07:02
| Global variable, e.g : int a=5 &

|-
| 07:07
| and local variable ,e.g:int sum

|-
| 07:12
| As an assignment,

|-
|07:14
|write a program to print the difference of two numbers.

|-
| 07:19
| Watch the video available at the link shown below .

|-
|07:22
|It summarizes the Spoken Tutorial project.

|-
|07:25
|If you do not have good bandwidth, you can download and watch it.

|-
| 07:30
| The Spoken Tutorial Project Team:

|-
|07:32
|Conducts workshops using spoken tutorials,

|-
|07:35
|Gives certificates to those who pass an online test .

|-
|07:40
|For more details, please write to,contact@spoken-tutorial.org

|-
| 07:47
| Spoken Tutorial Project is a part of the Talk to a Teacher project.

|-
|07:52
|It is supported by the National Mission on Education through ICT, MHRD, Government of India.

|-
|08:00
|More information on this Mission is available at the link shown below

|-
| 08:04
| This is Jean Bonnet from IIT Bombay signing off.

|-
|08:08
|Thank You for watching.

|}

@@ Line 13: / Line 13: @@
 |-
 | 00:11
-|* What is the Scope of variable?
+|What is the Scope of variable?
 |-
 | 00:13
-|* What is a Global variable?
+|What is a Global variable?
 |-
 | 00:16
-|* What is a Local variable?
+|What is a Local variable?
 |-
@@ Line 49: / Line 49: @@
 |-
 | 00:54
-|Depending on it's type and place of declaration it is divided into two categories:
+|Depending on it's type and place of declaration it is divided into two categories-
 |-
@@ Line 153: / Line 153: @@
 |-
 | 02:55
-| To compile, type
+| To compile, type '''gcc space scope.c space hyphen o space sco''' and press '''Enter'''.
-−
-|-
-| 02:56
-|'''gcc space scope.c space hyphen o space sco''' and press Enter.
 |-
 | 03:05
-|To execute,
+|To execute, type '''./sco''' (dot slash sco), press Enter.
-−
-|-
-| 03:06
-|type '''./sco''' (dot slash sco), press Enter.
 |-
@@ Line 256: / Line 248: @@
 |-
-|  05:19
+| 05:19
 | We can see  that it is similar to our C code.
@@ Line 289: / Line 281: @@
 |-
 |06:05
-|We see errors, '''redefinition of 'int a' ''' , ''' 'int a' previously defined here'''. Come back to our program.
+|We see errors, '''redefinition of 'int a', 'int a' previously defined here'''. Come back to our program.
 |-
@@ Line 312: / Line 304: @@
 |-
-|  06:36
+| 06:36
 | Delete this .
 |-
-|  06:39
+| 06:39
 | Click on Save.
 |-
-|  06:41
+| 06:41
 | Let us execute again.
@@ Line 328: / Line 320: @@
 |-
-|  06:45
+| 06:45
 |  Now  compile as before, execute as before.
@@ Line 357: / Line 349: @@
 |-
 |  07:07
-| and  local variable ,e.g:int sum
+| and  local variable ,e.g: int sum
 |-
 |  07:12
-|  As an assignment,
+|  As an assignment, write a program to print the difference of two numbers.
-−
-|-
-|07:14
-|write a program to print the difference of two numbers.
 |-
@@ Line 381: / Line 369: @@
 |-
 | 07:30
-| The Spoken Tutorial Project Team:
+| The Spoken Tutorial Project Team-
 |-

C-and-Cpp/C2/Scope-Of-Variables/English-USA - Revision history

Nancyvarkey at 08:50, 23 March 2017

Nancyvarkey: Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Scope of variables in C and C++'''. |- | 00:08 |In this tutorial we will learn..."