View source for C-and-C-Plus-Plus/C2/Relational-Operators-in-C-and-C-Plus-Plus/English-timed

 
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||'''Time'''

||'''Narration'''

|-
|00.02
| Welcome to the spoken tutorial on '''Relational Operators''' in '''C''' and '''C++'''.

|-
|00.07
|  In this tutorial, we will learn about:

|-
|00.09  	 	 	
|Relational operators like

|-
|00.12
|Less than: eg.  a < b 

|-
|00.15
|Greater than: eg. a > b

|-
|00.18
|Less than or equal to: eg.  a <= b 

|-
|00.23
|Greater than or equal to: eg. a >= b

|-
|00.28
|Equal to: eg. a == b

|-
|00.31
|Not equal to: eg. a != b

|-
| 00.38
|   To record this tutorial, I am using: '''Ubuntu 11.10''' as the operating system        

|-
|00.43
|'''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.

|-
|00.58
|Expressions using relational operators '''return''' 0 for false and 1 for true. 

'''Return''' values:

0 when '''False'''

1 when''' True''' 

|-
| 01.04
|  Now I will demonstrate the relational operators with the help of a C program.

|-
|  01.10
|   I have already made the program.

|-
|01.11
|So, I'll open the editor and explain the code.

|-
| 01.16
|  First, we declare two variables '''a '''and '''b'''.

|-
|  01.21
|  This '''printf''' statement prompts the user to enter the values of a and b.

|-
| 01.27 
|  This '''scanf '''statement takes input for the variables '''a '''and '''b'''.

|-
|  01.33
|   Now we have the '''greater than''' operator.

|-
|01.35
|This operator compares the two operands on either side of the operator.

|-
|01.39
|It '''returns''' ''False''' if '''a''' is greater than '''b'''.

|-
|  01.44
|  This '''printf '''statement is executed if the above condition is true.

|-
|01.48
|If the above condition is '''false '''then it is skipped.

|-
|01.51
|To control then jumps to the next statement.

|-
| 01.54
|  We now have the '''less than''' operator.

|-
|01.56
|This too compares the operands.

|-
|01.58
|It '''returns''' '''true''' when '''a''' is less than '''b'''.

|-
| 02.03
|This '''printf''' statement is executed if the above condition is '''true.'''

|-
|02.07
|It is skipped otherwise.

|-
|02.09
|  Let's execute the code till here.

|-
|02.13
|First comment out the following. Type /*  */ ''' '''

|-
| 02.24
|  Click on '''Save'''.

|-
|02.26
|I have saved my file as relational.c

|-
| 02.30
|   Open the terminal window by pressing '''Ctrl, Alt and T '''keys''' '''simultaneously.

|-
| 02.36
|  To compile, type the following on the terminal '''gcc relational.c -o rel'''

|-
| 02.50
|  Press '''Enter'''.

|-
| 02.52
|  To execute   type '''./rel''' Press '''Enter'''.

 
|-
| 02.58
|  I enter '''a''' as 8 and '''b '''as 3.

|-
| 03.02
|  The output is displayed:

|-
| 03.04
|  8 is greater than 3.

|-
| 03.07
|  You can try executing this code with different values of '''a '''and '''b'''.

|-
|03.12
| Coming back to  the code.

|-
| 03.14
|  Delete the comment from here  and  put it    here.

 

|-
| 03.24
|Now we have the '''less than or equal to '''operator.

|-
| 03.29
|  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'''.

|-
|03.39
| This '''printf '''statement is executed if the above condition is true.

|-
| 03.43
|  If the above condition is '''false '''then it is skipped.

|-
| 03.46
|  The control then jumps to the next statement.

|-
| 03.50
| Next comes the '''greater than or equal to '''operator.

|-
| 03.53
|  It compares '''a '''and '''b '''and '''returns''' '''true''' if '''a''' is greater than or equal to '''b'''.

|-
| 04.01
| If the condition is true then this printf statement will be executed.

|-
| 04.05
| Now let's execute the code till here.

|-
| 04.08
|  Click on '''Save'''.

|-
| 04.10
|  Switch back to the terminal.

|-
| 04.12
|  Compile and execute as before.

 
|-
| 04.17
|  I enter '''a''' as 8 and '''b '''as 3.

|-
| 04.23
|  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 ands 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.'''

|-
| 05.01
|  If not, the control then jumps on to the next statement.

|-
|05.06
|Similarly, we have the '''not equal to''' operator.

|-
| 05.09
|  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'''.

|-
|  05.21
|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.


|-
| 05.33
|  Enter '''a''' as 8 and '''b '''as 3.

|-
| 05.39
|  The output is displayed on the screen:

|-
| 05.41
|  8 is not equal to 3 

|-
| 05.45
|  So, we see how the relational operaotors work.

|-
| 05.48
|  Try executing this code with different set of inputs.

|-
| 05.52
| \Now, writing a smilar program in '''C++''' is quite easy.

|-
| 05.56
|  There are a few differences in the syntax.

|-
| 06.00
|  I have already made the code in '''C++'''.

|-
|06.04
| Their is the code for '''relational operators''' in '''C++'''.

|-
|06.09
|Notice that the header is different.

|-
| 06.12
|  Also we have the '''using '''statement here.

|-
| 06.16
|  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.

|-
|06.27
| Click on save.

|-
| 06.29
|  Please make sure the file is saved with the extension '''.cpp'''

|-
| 06.33
|  I have saved my file as '''relational.cpp'''

|-
| 06.38
| Let's compile the code.

|-
| 06.40
|  Open the terminal and type '''g++ relational.cpp -o rel1'''

|-
| 06.51
|  To  execute Type  '''./ rel1'', Press Enter.
 

 
|-
| 06.57
|  I enter '''a''' as 8 and '''b '''as 3.

|-
| 07.01
|  The output is displayed:

|-
| 07.03
|  We see that the output is same as  the one in  '''C''' code.

|-
| 07.08
| Now let us see an error which we can come across.

|-
| 07.11
|  Come back to the program

|-
| 07.13
| Suppose here we replace the double equal to sign with the single equal to.

|-
| 07.20
|  Click on '''Save.'''

|-
| 07.21
|  Come back to the terminal.

|-
| 07.24
|  Compile and execute as before.

|-
|  07.34
| Here we see it is showing 3 is equal to 3.

|-
| 07.38
|  Come back to our program

|-
| 07.40
|  This is because here we have an assignment operator.

|-
| 07.44
|  So value of b is assigned to a.

|-
|  07.47
|Now   Let us fix this error.

|-
| 07.49
|  Type an equal to sign.

|-
| 07.52
|  Click on '''Save'''

|-
|  07.55
|  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.

|-
| 08.09
|  In this tutorial, we learnt

|-
| 08.10
|  Relational operators like

|-
| 08.12
|  Less than:  eg. a <b 

|-
| 08.15
|  Greater than: eg. a>b

|-
| 08.18
|  Less than or equal to:  eg. a<=b 

|-
| 08.23
|  Greater than or equal to: eg. a>=b

|-
| 08.27
|  Equal to: eg. a==b

|-
| 08.30
|  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.

|-
| 08.40
|  Compare the marks to see which student has scored the highest.

|-
| 08.44
|  Check also if two or more students have scored equal marks.

|-
|  08.49
|  Watch the video available at the following link 
|-
| 08.51
|  It summarises 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 

|-
|  09.35
|  This is Ritwik Joshi from IIT Bombay. 

Thank you for joining. 

|}