C-and-C++/C2/Logical-Operators/English-timed

Time'	Narration
00.02	Welcome to the spoken tutorial on Logical operators in C and C++.
00.08	In this tutorial we will learn about:Logical operators like Logical AND eg. expression1 && expression2
00.16	Logical OR eg. expression1 or expression2
00.21	Logical NOT eg. not (Expression1)
00.25	We will do this with the help of examples.
00.28	To record this tutorial, I am using:Ubuntu 11.10 as the operating system
00.33	gcc and g++ Compiler version 4.6.1 on Ubuntu.
00.39	Let us start with the introduction to the logical operators.
00.43	In C and C++, true is any value other than 0.
00.48	non zero means true
00.50	And zero means false
00.53	Expressions using logical operators return 1 for true and 0 for false.
00.58	Now I'll explain the logical operators with the help of an example.
01.03	Here is the program for logical operators in C.
01.08	Inside the main block
01.10	This statement declares the variables a,b and c as integers.
01.16	The printf statement prompts the user to enter the values of a,b and c.
01.21	The scanf statement takes input from the user for variables a, b and c.
01.28	Here, We are comparing the values of a with b and c to find the greatest.
01.33	To compare simultaneously, we use the logical AND operator.
01.38	Here, all of the conditions have to be true for logical AND to return a true value.
01.43	The expression is not evaluated further on encountering a false condition.
01.49	So, the expression (a>c) is evaluated only if (a>b) is true.
01.56	If a is less than b, then the expression won't be evaluated further.
02.02	This statement is evaluated if the previous condition is true.
02.07	Next (b>c) is evaluated.
02.10	If the condition is true, then b is greatest is displayed on the screen.
02.16	Otherwise c is greatest is displayed on the screen.
02.21	We now come to the logical OR operator.
02.24	Here, any one of the conditions has to be true for logical OR to return a true value.
02.30	The expression is not evaluated further on encountering a true condition.
02.35	So, if a == zero, then the remaining two expressions won't be evaluated.
02.43	This printf statement is executed if either of a, b or c is 0.
02.49	Coming to the end of the program. return 0 and ending curly bracket.
02.54	Now save the program.
02.57	Save it with extension .c
03.00	I have saved my file as logical.c
03.03	Open the terminal by pressing Ctrl, Alt and T keys simulataneously.
03.08	To compile the code type gcc space logical dot c space minus o space log Press enter
03.23	To execute type ./log
03.27	Press Enter.
03.29	I will enter the values as, 0 34 567
03.39	The output is displayed as,
03.42	c is greatest.
03.45	The product of a, b and c is zero.
03.50	You should try executing this program with different sets of inputs.
03.55	Now Let's write the same program in C++
03.59	I have already made the program and will take you through it.
04.03	Here is the code in C++.
04.06	Now to make the same program in C++, we make a few changes.
04.11	There's a change in the header file.
04.14	Using statement has been used.
04.18	Also there is a difference in output and input statements.
04.21	The operators behave in the same way as they did in C.
04.25	Click on Save.
04.27	Make sure the file is saved with extension .cpp
04.31	Open the terminal by pressing Ctrl, Alt and T keys simulataneously.
04.36	To compile the program type g++ logical.cpp space minus o space log1. Press Enter
04.49	to execute type ./log1
04.53	press Enter.
04.56	I will enter the values as 0 34 567
05.02	So we see the output is similar to the C program.
05.05	You should try executing the program with different sets of inputs too.
05.10	Now let us see an error which we can come across.
05.12	Let's switch to the editor.
05.16	Suppose here we forgot the brackets.
05.20	Delete this and this.
05.26	Let see what will happen, Save the program.
05.30	Come back to the terminal
05.32	Compile and execute as before
05.38	We see the error:
05.41	Expected identifier before '(' token.
05.45	This is because we have two different expressions here
05.48	We have to evaluate them as one expression using AND operator.
05.53	Now let us go back to our program and fix the error
05.57	Let us insert the brackets here and here.
06.04	Click on Save
06.06	Come back to the terminal.
06.09	Compile and execute as before
06.14	So it is working now.
06.22	Let us now summarize the tutorial.
06.24	In this tutorial we learnt about Logical AND eg. ((a > b) && (a > c))
06.32	Logical OR eg. (a == 0 || b == 0 || c == 0)
06.39	Assignment
06.41	Write a program that takes two numbers as input from the user.
06.44	Check whether the two numbers are equal or not using NOT operator. Hint: (a != b)
06.54	Watch the video available at the following link
06.57	It summarises the Spoken Tutorial project
06.59	If you do not have good bandwidth, you can download and watch it
07.03	The Spoken Tutorial Project Team * Conducts workshops using spoken tutorials
07.07	Gives certificates for those who pass an online test
07.11	For more details, please write to contact at spoken hyphen tutorial dot org
07.18	Spoken Tutorial Project is a part of the Talk to a Teacher project
07.21	It is supported by the National Mission on Education through ICT, MHRD, Government of India
07.27	More information on this Mission is available at
07.30	spoken hyphen tutorial dot org slash NMEICT hyphen Intro
07.37	This is Ritwik Joshi from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Ashwini, PoojaMoolya, Pratik kamble, Sandhya.np14