C-and-C++/C2/Relational-Operators/English-timed
From Script | Spoken-Tutorial
Revision as of 12:45, 23 June 2014 by PoojaMoolya (Talk | contribs)
Time | Narration |
---|---|
00:01 | Welcome to the spoken tutorial on Relational Operators in C and C++. |
00:06 | In this tutorial, we will learn about: |
00:09 | Relational operators like |
00:11 | Less than: eg. a < b |
00:14 | Greater than: eg. a > b |
00:17 | Less than or equal to: eg. a <= b |
00:22 | Greater than or equal to: eg. a >= b |
00:27 | Equal to: eg. a == b |
00:30 | Not equal to: eg. a != b |
00:37 | To record this tutorial, I am using: Ubuntu 11.10 as the operating system |
00:42 | gcc and g++ Compiler version 4.6.1 in Ubuntu.
|
00:50 | Let us begin with an introduction. |
00:53 | Relational operators are used to compare integer and floating point numbers. |
00:57 | Expressions using relational operators return 0 for false and 1 for true. |
01:04 | Now I will demonstrate the relational operators with the help of a C program. |
01:09 | I have already made the program. |
01:11 | So, I'll open the editor and explain the code. |
01:15 | First, we declare two variables a and b. |
01:20 | This printf statement prompts the user to enter the values of a and b. |
01:26 | This scanf statement takes input for the variables a and b. |
01:32 | Now we have the greater than operator. |
01:35 | This operator compares the two operands on either side of the operator. |
01:38 | It returns' True if a is greater than b. |
01:43 | This printf statement is executed if the above condition is true. |
01:47 | If the above condition is false then it is skipped. |
01:50 | The control then jumps to the next statement. |
01:53 | We now have the less than operator. |
01:56 | This too compares the operands. |
01:57 | It returns true when a is less than b. |
02:02 | This printf statement is executed if the above condition is true. |
02:06 | It is skipped otherwise. |
02:09 | Let's execute the code till here. |
02:13 | First comment out the following. |
02:16 | Type /* |
02:21 | */ |
02:24 | Click on Save. |
02:26 | I have saved my file as relational.c |
02:29 | Open the terminal window by pressing Ctrl, Alt and T keys simultaneously. |
02:35 | To compile, type the following on the terminal gcc space relational dot c space -o space rel |
02:49 | Press Enter. |
02:51 | To execute type ./rel Press Enter.
|
02:56 | I enter a as 8 and b as 3. |
03:01 | The output is displayed: |
03:03 | 8 is greater than 3. |
03:07 | You can try executing this code with different values of a and b. |
03:11 | Coming back to the code. |
03:14 | Delete the comment from here |
03:18 | and put it here. |
03:24 | Now we have the less than or equal to operator. |
03:28 | This operator compares the two operands on either side of the operator. |
03:33 | It returns true if a is less than or equal to b. |
03:38 | This printf statement is executed if the above condition is true. |
03:42 | If the above condition is false then it is skipped. |
03:45 | The control then jumps to the next statement. |
03:49 | Next comes the greater than or equal to operator. |
03:52 | It compares a and b and returns true if a is greater than or equal to b. |
04:00 | If the condition is true then this printf statement will be executed. |
04:05 | Now let's execute the code till here. |
04:07 | Click on Save. |
04:09 | Switch back to the terminal. |
04:12 | Compile and execute as before.
|
04:17 | I enter a as 8 and b as 3. |
04:22 | The output is displayed: |
04:25 | 8 is greater than or equal to 3 |
04:30 | Now Coming back to rest of the code. |
04:33 | Delete the multiline comments from here |
04:39 | and here. |
04:43 | we now have the equal to operator. |
04:47 | It is denoted by double equal (==) signs. |
04:50 | This operator returns true when both operands are equal to one another. |
04:57 | This printf statement executes when a is equal to b. |
05:00 | If not, the control then jumps on to the next statement. |
05:06 | Similarly, we have the not equal to operator. |
05:08 | This operator returns true when the operands are not equal to one another. |
05:15 | This printf statment will execute when a is not equal to b. |
05:20 | Coming to the end of the program.
Return 0; |
05:24 | Click on Save. |
05:26 | Switch back to the terminal. |
05:28 | Compile and execute as before.
|
05:32 | Enter a as 8 and b as 3. |
05:38 | The output is displayed on the screen: |
05:40 | 8 is not equal to 3 |
05:44 | So, we see how the relational operaotors work. |
05:48 | Try executing this code with different set of inputs. |
05:51 | Now, writing a similar program in C++ is quite easy. |
05:56 | There are a few differences in the syntax. |
05:59 | I have already made the code in C++. |
06:04 | Here is the code for relational operators in C++. |
06:08 | Notice that the header is different. |
06:12 | Also we have the using statement here. |
06:15 | The output statement in C++ is cout. |
06:19 | And the input statement in C++ is cin. |
06:22 | So, apart from these differences, the two codes are very similar. |
06:26 | Click on save. |
06:28 | Please make sure the file is saved with the extension .cpp |
06:32 | I have saved my file as relational.cpp |
06:37 | Let's compile the code. |
06:39 | Open the terminal and type g++ relational.cpp space minus o space rel1 |
06:50 | To execute Type './ rel1, Press Enter. |
06:56 | I enter a as 8 and b as 3. |
07:00 | The output is displayed: |
07:02 | We see that the output is same as the one in C program. |
07:07 | Now let us see an error which we can come across. |
07:10 | Come back to the program |
07:13 | Suppose here we replace the double equal to sign with the single equal to. |
07:19 | Click on Save. |
07:21 | Come back to the terminal. |
07:23 | Compile and execute as before. |
07:33 | Here we see it is showing 3 is equal to 3. |
07:37 | Come back to our program |
07:40 | This is because here we have an assignment operator. |
07:43 | So value of b is assigned to a. |
07:46 | Now Let us fix this error. |
07:49 | Type an equal to sign. |
07:51 | Click on Save |
07:54 | Switch back to the terminal |
07:56 | compile and execute as before. |
08:04 | The output is now correct. |
08:06 | Let's summarize the tutorial. |
08:08 | In this tutorial, we learnt |
08:10 | Relational operators like |
08:12 | Less than: eg. a < b |
08:14 | Greater than: eg. a>b |
08:17 | Less than or equal to: eg. a<=b |
08:22 | Greater than or equal to: eg. a>=b |
08:27 | Equal to: eg. a==b |
08:29 | Not equal to: eg. a!=b |
08:34 | As an assignment |
08:35 | Write a program that takes the marks of three students as input. |
08:39 | Compare the marks to see which student has scored the highest. |
08:43 | Check also if two or more students have scored equal marks. |
08:48 | Watch the video available at the following link |
08:51 | It summarizes the Spoken Tutorial project |
08:54 | If you do not have good bandwidth, you can download and watch it |
08:58 | The Spoken Tutorial Project Team |
09:00 | Conducts workshops using spoken tutorials |
09:03 | Gives certificates for those who pass an online test |
09:06 | For more details, please write to contact at spoken hyphen tutorial dot org
|
09:14 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
09:18 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
09:24 | More information on this Mission is available at |
09:27 | spoken hyphen tutorial dot org slash NMEICT hyphen Intro |
09:34 | This is Ritwik Joshi from IIT Bombay.
Thank you for joining. |
Contributors and Content Editors
Ashwini, PoojaMoolya, Pratik kamble, Priyacst, Sakinashaikh, Sandhya.np14