Ruby/C2/Arithmetic-and-Relational-Operators/Gujarati

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Time Narration
00:01 Welcome to the Spoken Tutorial on Arithmetic & Relational Operators in Ruby.
00:06 In this tutorial we will learn about
00:08 Arithmetic Operators
00:10 Operator Precedence
00:12 Relational Operators
00:14 Here we are using Ubuntu Linux version 12.04 Ruby' 1.9.3
00:23 To follow this tutorial you must know how to use Terminal and Text editor in Linux.
00:28 You must also be familiar with irb
00:31 If not, for relevant tutorials, please visit our website
00:34 Now let us learn about arithmetic operators.
00:38 Ruby has following arithmetic operators.


00:42 +Addition: eg. a+b.
00:45 - Subtraction: eg. a-b.
00:48 / Division: eg. a/b.
00:51 * Multiplication: eg. a*b.
00:55  % Modulus: eg. a%b.
00:59 ** Exponent : eg a**b
01:04 Let us try these arithmetic operators using irb.
01:08 Open the terminal by pressing Ctrl, Alt and T keys simultaneously.
01:14 A terminal window appears on your screen.
01:17 Type irb and press Enter to launch the interactive Ruby.
01:21 Type 10 plus 20 and press Enter.
01:25 The addition operation is performed and the result 30 is displayed.
01:31 Similarly the subtraction and multiplication operations can be performed.
01:35 Let us try the division operator.
01:38 Type 10 slash 4
01:40 and press Enter.
01:42 Here you can see the result is truncated to the nearest whole number which is 2.
01:47 To get a more accurate answer, we need to express one number as float
01:52 Type 10.0 slash 4
01:56 and press Enter.


01:58 Now we get the result as 2.5
02:01 Let's now try the modulus operator.
02:05 The modulus operator returns the remainder as output.


02:09 Type 12 percentage sign 5 and press Enter
02:15 Here 12 is divided by 5 and the remainder 2 is returned back.
02:21 Now let's try the exponent operator.
02.24 Type 2 followed by the asterisk symbol twice and then 5 and press Enter.
02:32 This means that 2 is raised to the power of 5.
02:36 So we get the output as 32.
02:39 Next, let us learn about operator precedence.
02:44 When several operations occur in a mathematical expression,
02:47 each part is evaluated
02:50 and resolved in a predetermined order called operator precedence.
02:56 This means that the operator which has highest priority is executed first.
03:01 This is then followed by the next operator in the priority order and so on.


03:07 This slide lists all operators from highest precedence to lowest.
03:13 For example 3 + 4 * 5 returns 23 and not 35
03:23 The multiplication operator (*) has higher precedence than the addition operator (+)
03:29 and thus will be evaluated first.


03:32 Hence four fives are twenty and then three is added to 20 to give the output as 23
03:42 Lets us see some more examples based on operator precedence.
03:47 Let's go back to the terminal.
03:50 Press Crtl and L keys simultaneously to clear the irb console.
03:56 Now type 7 minus 2 multiply by 3
04:03 and press Enter
04:05 We get the answer as 1.
04:08 Here the asterisk symbol has higher priority than the minus sign.


04:13 So the multiplication opertion is performed first and then subtraction is performed.


04:20 Lets us see an another example.
04:22 Type Within brackets 10 plus 2 slash 4
04:29 and Press Enter
04:30 We get the answer as 3.
04:33 In this case () bracket has the higher priority than division (slash)
04:39 So the operation inside the bracket that is addition is performed first.
04:44 Then division is performed.
04:47 Now, let us learn about Relational Operators.
04:51 Let's switch back to slides.
04:54 Relational operators are also known as comparison operators.
04:59 Expressions using relational operators return boolean values.
05:04 Relation Operators in Ruby are
05:07 == Equals to Eg. a==b
05:14 dot eql question mark Eg. a.eql?b
05:21 != Not equals to Eg. a exclamation equal b
05:28 Less than Eg. a < b
05:32 Greater than Eg. a > b
05:37 <= Lesser than or equal to Eg.a less than arrow equal b
05:44 >= Greater than or equal to Eg.a greater than arrow equal b
05:49 <=> Combined comparison Eg.a less than arrow equal greater than arrow b
05:56 Now let us try some of these operators.
06:00 Go to the terminal.
06:02 Press ctrl, L keys simultaneously to clear the irb console.
06:09 Lets us try equals to operator.
06:11 So type 10 equals equals 10


06:16 and Press Enter
06:17 We get the output as true.
06:20 .eql? opeartor is same as equals to operator.
06:24 Lets try it out
06:25 Now type 10 .eql?10 and Press Enter
06:33 We get the output as true
06:35 Now lets try not equal to operator.
06:39 Type 10 not equal 10
06:44 And Press Enter
06:46 We get the output as false.
06:48 This is because the two numbers are equal.


06:51 Clear the irb console by pressing Ctrl, L simultaneously.
06:56 Let us now try less than operator.
07:00 Type 10 less than 5 and Press Enter


07:05 Here if first operand is less than second then it will return true
07:10 otherwise it will return false


07:14 We get the output as false because 10 is not less than 5
07:19 We will now try greater than operator
07:22 Type 5 greater than 2
07:26 Here if first operand is greater than second then it will return true
07:31 otherwise it will return false
07:34 Press Enter
07:36 In this case, we get the output as True because 5 is indeed greater than 2
07:42 Clear the irb console by pressing Ctrl, L simultaneously
07:47 We will now try the less than equal to operator
07:51 Type 12 less than equal 12


07:56 and Press Enter


07:59 Here if first operand is less than or equal to second then it returns true
08:04 otherwise it returns false
08:07 We get the output as True because 12 is equal to 12
08:11 You can try out the greater than or equal to operator likewise.
08:15 Now let's try the combined comparision operator.
08:19 The combined comparision operator
08:21 Returns 0 if first operand equals second


08:24 Returns 1 if first operand is greater than the second and


08:29 Returns -1 if first operand is less than the second operand


08:34 Let's see how it works with an example
08:36 Type 3 less than equals greater than 3
08:41 And Press Enter


08:43 We get the output as 0
08:45 because both the operands are equal i.e. both are three
08:50 Now, let's change one of the operands to 4
08:53 Type 4 less than equals greater than 3


08:58 And Press Enter
08:59 We get the output as 1
09:01 Since 4 is greater than 3


09:04 Now, let's change this example again
09:07 Type 4 less than equals greater than 7


09:11 And Press Enter
09:13 We get the output as -1
09:14 Since 4 is less than 7


09:17 As an assignment
09:19 Solve the following examples using irb and check the output
09:24 10 + bracket 2 astreisk 5 bracket 8 slash 2
09:32 4 astreisk 5 slash 2 plus 7
09:37 Also, try arithmetic operators using methods
09:42 This brings us to the end of this Spoken Tutorial.


09:45 Let's summarize


09:47 In this tutorial we have learnt about
09:49 Arithmetic Operators plus minus astreisk slash standing for addition, subtraction, multiplication, division.
09:59 Operator Precedence
10:01 Relational Operators
10:04 using many examples
10:06 Watch the video available at the following link.
10:10 It summarises the Spoken Tutorial project.
10:14 If you do not have good bandwidth, you can download and watch it.
10:18 The Spoken Tutorial Project Team :
10:20 Conducts workshops using spoken tutorials
10:23 Gives certificates to those who pass an online test
10:26 For more details, please write to contact@spoken-tutorial.org
10:32 Spoken Tutorial Project is a part of the Talk to a Teacher project.
10:36 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:43 More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro
10:51 This script has been contributed by the spoken tutorial team IIT Bombay
10:57 And this is Anjana Nair signing off Thank you


Contributors and Content Editors

Jyotisolanki, PoojaMoolya