View source for C-and-C++/C2/Nested-If-And-Switch-Statement/English-timed

{| border=1
|| '''Time'''
|| '''Narration'''
|-
|  00:01
|  Welcome to the spoken tutorial on '''Nested if''' and '''Switch statements in C and C++'''.

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| 00:07
|   In this tutorial we will learn, 

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|  00:09
| how to use '''nested if''' statement and

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|  00:12
| '''switch''' statement.We will do this with the help of some examples.

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|   00:17
|  To record this tutorial, I am using

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|  00:20
| '''Ubuntu operating system version 11.10''',

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|  00:24
| '''gcc and g++ Compiler version 4.6.1 on Ubuntu'''.

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| 00:30
|  First we will learn how to write '''nested if''' and '''switch''' statements with an example.

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|  00:36
| I have already written the program. 

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| 00:39
|  Let’s have a look. In this program we will learn to check the range of integers.

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|   00:45
|  Note that our file name is '''nested-if.c'''.

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|   00:50
|  Let me explain the code now.

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|  00:52
|  This is our Header file.

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|  00:54
|  This is our  main() function.
 
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|  00:56
| Inside the main() function we have declared two integer variables ''''x and y''''.

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|   01:02
|Here we prompt the users to enter a number between the range of''' 0 to 39'''.
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| 01:08
|  We take the value of '''y''' as input from the user.

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|  01:12
| This is our '''if''' condition. 

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|   01:14
| Here, we will check whether y/10=0.

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|  01:19
| If the condition is true, we print '''"you have entered the number in the range of 0-9".'''

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| 01:25
| This is our '''else-if''' condition.

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|  01:28
|  Here we check that y/10 equals to 1.
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|  01:32
|If the condition is true,

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|  01:34
| we print ''' "you have entered a number in the range of 10-19".'''

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|   01:39
|In this '''else if''' condition we check whether the number is in the range of 20-29.
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|  01:45
| And here we will see that the number is in the range of 30 to 39.
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|  01:51
|  This is our '''else''' condition.

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|  01:53
|  If all of the above conditions are false,

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|  01:55
| we print''' "number not in range".'''

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|  01:58
| And this is our '''return''' statement.
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|  02:01
|  Now let us execute the program.

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|  02:03
| Please open the terminal window by pressing '''Ctrl+Alt''' and '''T''' keys simultaneously on your keyboard.

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| 02:12
|To execute, type '''gcc space nested-if.c space hyphen o space nested'''. Press '''Enter'''.

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| 02:23
| Type dot slash “nested” (./nested). Press '''Enter'''.

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|  02:28 
| We see '''Enter a number between 0 to 39'''. 

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| 02:32  
| I will enter '''12'''.

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| 02:34
| | The output is displayed as:

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|  02:35
|''' you have entered the  number  in the range of 10-19'''.

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|  02:40
| Let us enter another number.
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|  02:42
|   Let's execute again. Press the up arrow key, press '''Enter'''.

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|  02:48
| I will give ''' 5''' this time.

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|   02:50
| We see the output as :

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|  02:52
|  '''you have entered the number in the range of 0-9'''.

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|  02:56
|  The conditional execution can also be done in another way.

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|  03:00
| By using '''switch''' statement. 

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|  03:02
| Let’s see how it is done.

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| 03:05
| We will see  the same program using '''switch'''.

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|  03:08
| I have already opened the program.

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|  03:10
|  Let's switch back to our text editor.
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|  03:13
|I have explained this in the previous program.    

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| 03:16	
|So I will move on to the '''switch''' statements.
   
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| 03:20
||Here, we divide the inputs i.e '''y'''  by 10 and the result  is  stored in  the variable '''x'''.

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|03:28  
| That means the quotient will be stored in x.

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|  03:32
| With the help of the quotient we can identify the range of the number.

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|  03:36
|  Here, we tell the switch command that the variable to be checked is '''x'''.

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|  03:41 
|This is '''case 0''' . If case 0 is satisfied 

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|  03:45
| then we print '''you have entered  the number in the range of 0-9.'''

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| 03:51
| We add '''break '''to come out of the loop if the case is satisfied.

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|  03:55
| We need to '''break '''the loop each time. 

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|  03:58	
| It is because only one condition can be true at a time.

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| 04:03
|This is “case 1”. “case 1” means “if the value of '''x '''is 1”.
 
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|  04:08
| We print '''you have entered a number in the range of 10-19.'''

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|   04:12
| This is   “case 2” . 

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|  04:14
|Here  we print '''you have entered a number in the range of 20-29.'''

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| 04:20
| And this is case 3. Here we check whether the number is in the range of 30-39.

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| 04:26
| This is the default case. Default case specifies what needs to be done if none of the above cases are satisfied.

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|  04:36
| Here we print "number not in range".

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|  04:39
| And This is our '''return''' statement.

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|  04:41
| Let us execute the program.

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|  04:43
|Switch back to the terminal.

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|  04:46
|Type '''gcc space switch.c space -o space switch'''. Press Enter.

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| 04:55 
| Type '''./switch'''(dot slash switch). Press Enter.

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|  05:00
| Enter a number between 0 to  39. I will enter 35.

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|  05:06
|  The output is displayed as “you have entered the number in the range of 30 to 39”.

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|  05:10
| Now we will see how to execute the programs  in C++.

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| 05:16
|Switch back to the text editor.

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|  05:18
| Note that our file name is '''nested-if.cpp'''.

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|  05:23
| Here the logic and implementation are same.

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|  05:27
|  There are a few changes like:

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|  05:30
|The header file as "iostream" in place of "stdio.h".

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|  05:35
|Here we have included the '''using''' statement

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|  05:39
|'''Using namespace std'''.

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|  05:41
|And the  '''cout''' and '''cin''' function in place of '''printf''' and '''scanf'''.

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|  05:46
|You can see that the rest of the code is similar to our C program.

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|  05:51
|Let’s execute the code.

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|  05:53
|Come back to the terminal.

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|  05:56
|Type '''g++ space nested-if.cpp space -o space nested1'''. Press Enter.

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|  06:07
|Type '''./nested1'''. Press Enter.

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|  06:11
| Enter a number between 0 to 39. I will enter 40.

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|  06:16 
| The output is displayed as: “number not in range”

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|  06:20
|Now let’s see the switch program in C++.

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|  06:24
| Come back to our text editor.
 
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|  06:27
| Here also the logic and implementation are same.

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|  06:31
| You can see that the  header file is '''iostream'''.

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|  06:34
| Here is the '''using''' statement.

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|  06:37
| And we have changed the '''cout''' and '''cin''' function.

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|  06:41
| Rest of the code is similar to our switch.c program.

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|  06:45
| Let us execute.Come back to our terminal.
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|  06:48
|Type '''g++ space switch.cpp space -o space switch1'''. Press Enter.
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|  06:58
| Type '''./switch1'''. Press Enter.
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|  07:02
| Enter a number between 0 to 39.
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|  07:05
|  I will enter 25.
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|  07:09
|  The output is displayed as:
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|  07:11
|  “you have entered  the number in the range of 20-29”

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|  07:15
|  Now let us switch back to our slides.
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| 07:18
|We will see the comparison between switch and nested-if statements.

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|  07:23
|  Switch statement is evaluated according to the result of the expression.
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|  07:28
|Netsed-if statement is run only if the result of the expression is true.
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|  07:34
|In '''switch''', we treat various values of the variable as '''cases'''. 
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|  07:39
|In nested-if we have to write the conditional statement for each value of the variable.

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|  07:45
|  Switch statement can only check the integer values.
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|  07:50
|  Nested if can check for both, integer and fractional values.
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|  07:55
|  This brings us to the end of this tutorial.
 
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| 07:58
|Let us summarize.
 
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| 08:00
|  In this tutorial, we learnt * 'nested if' statement. e.g. else if( y/10 equals to 0) 

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|08:08   
|switch statement. e.g. switch(x) and

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|  08:12
|Difference between nested-if and switch statements.
 
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|  08:16
| As an assignment,write a program to check whether the age of the employee is between 20 to 60.

|-
| 08:23
| Watch the video available at the link shown http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial.

|-
|  08:26
| It summarizes the Spoken Tutorial project.

|-
|  08:29
| If you do not have good bandwidth, you can download and watch it.

|-
|  08:33
|  The Spoken Tutorial Project Team, Conducts workshops using spoken tutorials.

|-
|  08:38
| Gives certificates to those who pass an online test.

|-
| 08:42
| For more details please write to contact @spoken-tutorial.org

|-
| 08:49 
|  Spoken Tutorial Project is a part of the Talk to a Teacher project.

|-
|  08:52
| It is supported by the National Mission on Education through ICT, MHRD, Government of India.

|-
|  08:58
| More information on this Mission is available at: [http://spoken-tutorial.org/ http://spoken-tutorial.org]\NMEICT-Intro.

|-
| 09:04
|  The script is contributed by Chaitanya Mokashi. This is Ashwini patil from IIT Bombay signing off. Thank you for joining.

|}