C-and-C++/C2/Nested-If-And-Switch-Statement/English-timed
From Script | Spoken-Tutorial
Time | Narration |
00:01 | Welcome to the spoken tutorial on Nested if and Switch statements in C and C++. |
00:07 | In this tutorial we will learn, |
00:09 | how to use nested if statement and |
00:12 | switch statement.We will do this with the help of some examples. |
00:17 | To record this tutorial, I am using |
00:20 | Ubuntu operating system version 11.10, |
00:24 | gcc and g++ Compiler version 4.6.1 on Ubuntu. |
00:30 | First we will learn how to write nested if and switch statements with an example. |
00:36 | I have already written the program. |
00:39 | Let’s have a look. In this program we will learn to check the range of integers. |
00:45 | Note that our file name is nested-if.c. |
00:50 | Let me explain the code now. |
00:52 | This is our Header file. |
00:54 | This is our main() function. |
00:56 | Inside the main() function we have declared two integer variables 'x and y'. |
01:02 | Here we prompt the users to enter a number between the range of 0 to 39. |
01:08 | We take the value of y as input from the user. |
01:12 | This is our if condition. |
01:14 | Here, we will check whether y/10=0. |
01:19 | If the condition is true, we print "you have entered the number in the range of 0-9". |
01:25 | This is our else-if condition. |
01:28 | Here we check that y/10 equals to 1. |
01:32 | If the condition is true, |
01:34 | we print "you have entered a number in the range of 10-19". |
01:39 | In this else if condition we check whether the number is in the range of 20-29. |
01:45 | And here we will see that the number is in the range of 30 to 39. |
01:51 | This is our else condition. |
01:53 | If all of the above conditions are false, |
01:55 | we print "number not in range". |
01:58 | And this is our return statement. |
02:01 | Now let us execute the program. |
02:03 | Please open the terminal window by pressing Ctrl+Alt and T keys simultaneously on your keyboard. |
02:12 | To execute, type gcc space nested-if.c space hyphen o space nested. Press Enter. |
02:23 | Type dot slash “nested” (./nested). Press Enter. |
02:28 | We see Enter a number between 0 to 39. |
02:32 | I will enter 12. |
02:34 | The output is displayed as: |
02:35 | you have entered the number in the range of 10-19. |
02:40 | Let us enter another number. |
02:42 | Let's execute again. Press the up arrow key, press Enter. |
02:48 | I will give 5 this time. |
02:50 | We see the output as : |
02:52 | you have entered the number in the range of 0-9. |
02:56 | The conditional execution can also be done in another way. |
03:00 | By using switch statement. |
03:02 | Let’s see how it is done. |
03:05 | We will see the same program using switch. |
03:08 | I have already opened the program. |
03:10 | Let's switch back to our text editor. |
03:13 | I have explained this in the previous program. |
03:16 | So I will move on to the switch statements. |
03:20 | Here, we divide the inputs i.e y by 10 and the result is stored in the variable x. |
03:28 | That means the quotient will be stored in x. |
03:32 | With the help of the quotient we can identify the range of the number. |
03:36 | Here, we tell the switch command that the variable to be checked is x. |
03:41 | This is case 0 . If case 0 is satisfied |
03:45 | then we print you have entered the number in the range of 0-9. |
03:51 | We add break to come out of the loop if the case is satisfied. |
03:55 | We need to break the loop each time. |
03:58 | It is because only one condition can be true at a time. |
04:03 | This is “case 1”. “case 1” means “if the value of x is 1”. |
04:08 | We print you have entered a number in the range of 10-19. |
04:12 | This is “case 2” . |
04:14 | Here we print you have entered a number in the range of 20-29. |
04:20 | And this is case 3. Here we check whether the number is in the range of 30-39. |
04:26 | This is the default case. Default case specifies what needs to be done if none of the above cases are satisfied. |
04:36 | Here we print "number not in range". |
04:39 | And This is our return statement. |
04:41 | Let us execute the program. |
04:43 | Switch back to the terminal. |
04:46 | Type gcc space switch.c space -o space switch. Press Enter. |
04:55 | Type ./switch(dot slash switch). Press Enter. |
05:00 | Enter a number between 0 to 39. I will enter 35. |
05:06 | The output is displayed as “you have entered the number in the range of 30 to 39”. |
05:10 | Now we will see how to execute the programs in C++. |
05:16 | Switch back to the text editor. |
05:18 | Note that our file name is nested-if.cpp. |
05:23 | Here the logic and implementation are same. |
05:27 | There are a few changes like: |
05:30 | The header file as "iostream" in place of "stdio.h". |
05:35 | Here we have included the using statement |
05:39 | Using namespace std. |
05:41 | And the cout and cin function in place of printf and scanf. |
05:46 | You can see that the rest of the code is similar to our C program. |
05:51 | Let’s execute the code. |
05:53 | Come back to the terminal. |
05:56 | Type g++ space nested-if.cpp space -o space nested1. Press Enter. |
06:07 | Type ./nested1. Press Enter. |
06:11 | Enter a number between 0 to 39. I will enter 40. |
06:16 | The output is displayed as: “number not in range” |
06:20 | Now let’s see the switch program in C++. |
06:24 | Come back to our text editor. |
06:27 | Here also the logic and implementation are same. |
06:31 | You can see that the header file is iostream. |
06:34 | Here is the using statement. |
06:37 | And we have changed the cout and cin function. |
06:41 | Rest of the code is similar to our switch.c program. |
06:45 | Let us execute.Come back to our terminal. |
06:48 | Type g++ space switch.cpp space -o space switch1. Press Enter. |
06:58 | Type ./switch1. Press Enter. |
07:02 | Enter a number between 0 to 39. |
07:05 | I will enter 25. |
07:09 | The output is displayed as: |
07:11 | “you have entered the number in the range of 20-29” |
07:15 | Now let us switch back to our slides. |
07:18 | We will see the comparison between switch and nested-if statements. |
07:23 | Switch statement is evaluated according to the result of the expression. |
07:28 | Netsed-if statement is run only if the result of the expression is true. |
07:34 | In switch, we treat various values of the variable as cases. |
07:39 | In nested-if we have to write the conditional statement for each value of the variable. |
07:45 | Switch statement can only check the integer values. |
07:50 | Nested if can check for both, integer and fractional values. |
07:55 | This brings us to the end of this tutorial. |
07:58 | Let us summarize. |
08:00 | In this tutorial, we learnt * 'nested if' statement. e.g. else if( y/10 equals to 0) |
08:08 | switch statement. e.g. switch(x) and |
08:12 | Difference between nested-if and switch statements. |
08:16 | As an assignment,write a program to check whether the age of the employee is between 20 to 60. |
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09:04 | The script is contributed by Chaitanya Mokashi. This is Ashwini patil from IIT Bombay signing off. Thank you for joining. |
Contributors and Content Editors
Ashwini, Kavita salve, Krupali, PoojaMoolya, Pratik kamble, Priyacst, Sandhya.np14, Sneha