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Nancyvarkey at 13:39, 18 August 2013

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Nancyvarkey at 07:58, 2 July 2013

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Nancyvarkey at 15:33, 22 April 2013

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Nancyvarkey: Created page with ''''Title of script''': Arithmetic & Relational Operators in Ruby '''Author:Spoken Tutorial Team, IIT Bombay''' '''Keywords: Arithmetic Operators, Relational Operators, video tu…'

2013-04-09T11:48:45Z

Created page with ''''Title of script''': Arithmetic & Relational Operators in Ruby '''Author:Spoken Tutorial Team, IIT Bombay''' '''Keywords: Arithmetic Operators, Relational Operators, video tu…'

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'''Title of script''': Arithmetic & Relational Operators in Ruby

'''Author:Spoken Tutorial Team, IIT Bombay'''

'''Keywords: Arithmetic Operators, Relational Operators, video tutorial'''

{| border=1
| '''Visual Cue'''
| '''Narration'''

|-
| Slide 1
| Welcome to the Spoken Tutorial on Arithmetic & Relational Operators in '''Ruby.'''

|-
| Slide 2

Learning Objectives
| In this tutorial we will learn about

* Arithmetic Operators
* Operator Precedence
* Relational Operators<br/>

|-
| Slide 3

System Requirements
| Here we are using

* '''Ubuntu linux''' version 12.04
* '''Ruby''' 1.9.3

|-
| Slide 4

Pre-requisites
| To follow this tutorial you must know how to use''' Terminal''' and Text editor in '''Linux.'''

You must also be familiar with '''irb'''

If not, for relevant tutorials, please visit our website

|-
| Slide 5

Arithmetic Operators

(need to change the slide)
| Now let us learn about arithmetic operators.

'''Ruby''' has following arithmetic operators.

+ Addition: eg. a+b.

- Subtraction: eg. a-b.

/ Division: eg. a/b.

<nowiki>* Multiplication: eg. a*b. </nowiki>

% Modulus: eg. a%b.

<nowiki>** Exponent : eg a**b</nowiki>

|-
|
| Let us try these arithmetic operators using '''irb'''.

|-
| Switch to the terminal

'''Press Ctrl+alt+t'''

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

A terminal window appears on your screen.

|-
| Type '''irb '''<nowiki><<press</nowiki>''' '''enter

| Type''' irb'''

and press''' Enter''' to launch the''' interactive Ruby.'''

|-
| Type '''10+ 20 '''<nowiki><<press</nowiki> enter
| Type '''10 plus 20'''

and press '''Enter'''.

|-
| Highlight''' 30'''
| The addition operation is performed and the result '''30''' is displayed.

|-
|
| Similarly the subtraction and multiplication operations can be performed.

|-
|
| Let us try the division operator.

|-
| Type '''10/4'''<nowiki><<press </nowiki>Enter
| Type '''10 slash 4'''

and press '''Enter'''.

|-
| Highlight''' 2'''
| Here you can see the result is truncated to the nearest whole number which is '''2.'''

|-
|
| To get a more accurate answer, we need to express one number as '''float'''

|-
| Type '''10.0/4 '''<nowiki><<press Enter</nowiki>
| Type '''10.0 slash 4'''

and press '''Enter'''.

|-
| Highlight '''2.5'''
| Now we get the result as '''2.5'''

|-
|
| Let's now try the '''modulus '''operator.

The '''modulus''' operator returns the remainder as output.

|-
| Type '''12%5'''

press Enter
| Type '''12 percentage sign 5 '''

and press '''Enter'''.

|-
| Highligtht '''2 '''
| Here '''12 '''is divided by '''5''' and the remainder''' 2 '''is returned back.

|-
|
| Now let's try the '''exponent''' operator.

|-
| Type''' 2**5'''<nowiki><<press </nowiki>'''enter'''
| Type '''2 followed by the asterisk symbol twice and then 5 '''and press '''Enter'''.

|-
|
| This means that '''2''' is raised to the power of '''5.'''

|-
| Highlight '''32'''
| So we get the output as '''32.'''

|-
|
| Next, let us learn about operator precedence.

|-
| Slide 6

'''What is Operator Precedence?'''

| When several operations occur in a mathematical expression,

* each part is evaluated
* and resolved in a predetermined order
* called '''operator precedence'''.

|-
| Slide 7

'''What is Operator Precedence?'''
| This means that the operator which has '''highest priority''' is executed first.

This is then followed by the next operator in the '''priority''' order and so on.

|-
| Slide 8

'''Operator Precedence'''
| This slide lists all operators from highest precedence to lowest.

'''{ } ( )''' -- 1st Priority

'''<nowiki>* </nowiki>/ %''' -- 2nd priority

'''+ -''' -- 3rd Priority

'''<nowiki>< </nowiki><nowiki><= </nowiki>> >=''' -- 4th Priority

'''<nowiki>= </nowiki><nowiki>= = </nowiki>!=''' -- 5th Prior and so on

|-
| Slide 9

Example of Operator Precedence

| For example -

'''3 + 4 * 5'''         returns '''23''' and not '''35'''

The multiplication operator ('''<nowiki>*</nowiki>''') has higher precedence than the addition operator ('''+''')

and thus will be evaluated first.

|-
| Highlight 4*5

Highlight 3+
| Hence four fives are twenty and then three is added to 20 to give the output as '''23'''

|-
|
| Lets us see some more examples based on operator precedence.

|-
| Switch back to the terminal.

Press '''Crtl+l'''
| Let's go back to the terminal.

Press''' Crtl and l''' keys simultaneously to clear the '''irb''' console.

|-
| Type

'''7-2*3'''<nowiki><< Press </nowiki>Enter
| Now type '''7 minus 2 multiply by 3 '''

and press '''Enter'''

|-
| Highlight '''1'''
| We get the answer as '''1.'''

Here the '''asterisk''' symbol has higher '''priority''' than the '''minus''' sign.

So the '''multiplication''' opertion is performed first and

then '''subtraction''' is performed.

|-
|
| Lets us see an another example.

|-
| Type

'''(10+2)/4'''<nowiki><<Press</nowiki> Enter

| Type

'''Within brackets 10 plus 2 slash 4'''

Press '''Enter'''

|-
| Highlight '''3'''
| We get the answer as '''3.'''

|-
|
| In this case '''() - bracket''' has the higher '''priority''' than '''/- division'''.

So the operation inside the bracket that is '''addition''' is performed first.

Then '''division''' is performed.

|-
|
| <nowiki><<Pause>></nowiki>

Now, let us learn about Relational Operators.

|-
|
| Let's switch back to slides.

|-
| Slide 10

Relational Operator
| Relational operators are also known as '''comparison''' operators.

Expressions using relational operators return '''boolean''' values.

|-
| Slide 11

Relational Operator
| Relation Operators in '''Ruby''' are

* '''<nowiki>==</nowiki>''' Equals to        Eg. a==b
* .eql? Equals to        Eg. a.eql?b
* '''!= '''Not equals to        Eg. a!=b
* '''<nowiki>< </nowiki>'''<nowiki>Less than        Eg. a<b</nowiki>
* '''>''' Greater than        Eg. a>b
* '''<nowiki><=</nowiki>''' <nowiki>Less than or equal to        Eg. a<=b</nowiki>
* '''>=''' Greater than or equal to         Eg. a>=b
* '''<nowiki><=> </nowiki>'''<nowiki>Combined comparison Eg. a<=>b</nowiki>

|-
|
| Now let us try some of these operators.

|-
| Switch back to the terminal

press ctrl+l
| Go to the terminal.

Press '''ctrl''' and '''L''' keys simultaneously to clear the '''irb''' console.

|-
| Type

'''<nowiki>10 == 10 << </nowiki>'''Press''' '''Enter
| Lets us try '''equals to''' operator.

So type

'''10 equals equals 10'''

Press '''Enter'''

|-
| Highlight''' true'''
| We get the output as '''true.'''

|-
|
| '''.eql?''' opeartor is same as '''equals to''' operator.

Lets try it out

|-
| Type

'''<nowiki>10 .eql?10 << </nowiki>'''Press''' '''Enter
| Now type

'''10 .eql?10'''

Press '''Enter'''

|-
| Highlight '''true'''
| We get the output as '''true'''

|-
| '''<nowiki>10 != 10<<</nowiki>'''Press''' '''Enter
| Now lets try '''not equal to '''operator.

Type

'''10 not equals 10'''

Press '''Enter'''

|-
| Highlight''' false '''
| We get the output as '''false.'''

This is because the two numbers are equal.

|-
| Press ctrl+l
| Clear the '''irb''' console by pressing '''Ctrl '''and '''L''' simultaneously.

|-
|
| Let us now try''' less than '''operator.

|-
| '''Type'''

'''<nowiki>10 < 5 </nowiki>'''
| Type

'''10 less than 5'''

|-
|
| Here if first operand is less than second then it will return '''true'''

otherwise it will return '''false'''

Press '''Enter'''

|-
| Highlight '''False'''
| We get the output as '''false '''because '''10''' is not less than '''5'''

|-
|
| We will now try '''greater than '''operator

|-
| Type

'''5 > 2'''
| Type

'''5 greater than 2 '''

|-
|
| Here if first operand is greater than second then it will return '''true'''

otherwise it will return '''false'''

|-
|
| Press '''Enter'''

|-
| Highlight '''True'''
| In this case, we get the output as '''True '''because '''5''' is indeed greater than '''2'''

|-
| Press ctrl+l
| Clear the '''irb '''console by pressing '''Ctrl '''and '''L''' simultaneously

|-
|
| We will now try the''' less than equal to '''operator

|-
| Type

'''<nowiki>12 <= 12 </nowiki>'''<nowiki><< Press </nowiki>Enter
| Type

'''12 less than equal to 12'''

Press '''Enter'''

|-
|
| Here if first operand is less than or equal to second then it returns '''true'''

otherwise it returns '''false'''

|-
|
| Press '''Enter'''

|-
| Highlight '''True'''
| We get the output as '''True '''because''' 12''' is equal to''' 12'''

|-
|
| You can try out the '''greater than or equal to''' operator likewise.

|-
|
| Now let's try the '''combined comparision''' operator.

|-
|
| The '''combined comparision''' operator

Returns '''0''' if first operand equals second

Returns '''1''' if first operand is greater than the second

and

Returns '''-1''' if first operand is less than the second operand

|-
| Type

'''<nowiki>3 <=> 3</nowiki>'''<nowiki> << Press </nowiki>'''Enter'''
| Let's see how it works with an example

Type

'''3 less than equals greater than 3'''

Press '''Enter'''

|-
| Highlight '''0'''
| We get the output as '''0'''

because both the operands are equal i.e. both are '''three'''

|-
| Type

'''<nowiki>4 <=> 3 << </nowiki>'''Press''' Enter'''
| Now, let's change one of the operands to '''4'''

Type

'''4 less than equals greater than 3'''

Press''' Enter'''

|-
| Highlight '''1'''
| We get the output as '''1 '''

Since''' 4''' is greater than '''3'''

|-
| Type

'''4<nowiki> <=> 7 << </nowiki>'''Press''' Enter'''
| Now, let's change this example again

Type

'''4 less than equals greater than 7'''

Press''' Enter'''

|-
| Highlight '''-1'''
| We get the output as '''-1'''

Since''' 4''' is less than '''7'''

<nowiki><pause></nowiki>

|-
| Slide11

Assignment
| As an assignment

Solve the following examples using '''irb''' and check the output

*'''10 + (2 * 5) – (8 / 2) = ?'''
*'''4*5/2+7=?'''
*Also, try arithmetic operators using methods

|-
|
| <nowiki><<Pause>></nowiki>

This brings us to the end of this Spoken Tutorial.

Let's summarize

|-
| Slide 12

Summary
| In this tutorial we have learnt about

* Arithmetic Operators + - * /
* Operator Precedence
* Relational Operators
* using many examples

|-
| Slide 13

About the Spoken Tutorial Project
| Watch the video available at the following link.

It summarises the Spoken Tutorial project.

If you do not have good bandwidth, you can download and watch it.

|-
| Slide 14
| The Spoken Tutorial Project Team :

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to

contact at spoken hyphen tutorial dot org

|-
| Slide 15

Acknowledgement
| Spoken Tutorial Project is a part of the Talk to a Teacher project.

It is supported by the National Mission on Education through ICT, MHRD, Government of India.

More information on this Mission is available at:

spoken hyphen tutorial dot org slash NMEICT hyphen Intro.

|-
| Slide 16

About the contributor

| This script has been contributed by the Spoken Tutorial Team, IIT Bombay

And the video has been contributed by Ruby Software Pvt. Ltd

[http://www.ruby-software.com/ http://www.ruby-software.com]

Thank you

|}

@@ Line 2: / Line 2: @@
 '''Author:Spoken Tutorial Team, IIT Bombay'''
 '''Keywords: Arithmetic Operators, Relational Operators, video tutorial'''
@@ Line 610: / Line 608: @@
 | This script has been contributed by the Spoken Tutorial Team, IIT Bombay
-And this is Aditi Gokarn from SNDT
+And this is Anjana Nair signing off
 Thank you
 |}

Ruby/C2/Arithmetic-and-Relational-Operators/English - Revision history

Nancyvarkey: Undo revision 5621 by Nancyvarkey (Talk)

Nancyvarkey at 13:39, 18 August 2013

Nancyvarkey at 07:58, 2 July 2013

Nancyvarkey at 15:33, 22 April 2013

Nancyvarkey: Created page with ''''Title of script''': Arithmetic & Relational Operators in Ruby '''Author:Spoken Tutorial Team, IIT Bombay''' '''Keywords: Arithmetic Operators, Relational Operators, video tu…'