Difference between revisions of "Ruby/C2/Arithmetic-and-Relational-Operators/English"
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'''Author:Spoken Tutorial Team, IIT Bombay''' | '''Author:Spoken Tutorial Team, IIT Bombay''' | ||
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'''Keywords: Arithmetic Operators, Relational Operators, video tutorial''' | '''Keywords: Arithmetic Operators, Relational Operators, video tutorial''' | ||
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| This script has been contributed by the Spoken Tutorial Team, IIT Bombay | | This script has been contributed by the Spoken Tutorial Team, IIT Bombay | ||
| − | And this is | + | And this is Anjana Nair signing off |
Thank you | Thank you | ||
|} | |} | ||
Revision as of 13:28, 2 July 2013
Title of script: Arithmetic & Relational Operators in Ruby
Author:Spoken Tutorial Team, IIT Bombay
Keywords: Arithmetic Operators, Relational Operators, video tutorial
| 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
|
| Slide 3
System Requirements |
Here we are using
|
| 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. * Multiplication: eg. a*b. % Modulus: eg. a%b. ** Exponent : eg a**b |
| 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 <<press enter | Type irb
and press Enter to launch the interactive Ruby. |
| Type 10+ 20 <<press 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<<press 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 <<press Enter | 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<<press 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,
|
| 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 * / % -- 2nd priority + - -- 3rd Priority < <= > >= -- 4th Priority = = = != -- 5th Prior and so on |
| Slide 9
Example of Operator Precedence |
For example -
3 + 4 * 5 returns 23 and not 35 The multiplication operator (*) 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<< Press 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<<Press 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. | |
| <<Pause>>
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
|
| 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
10 == 10 << 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
10 .eql?10 << Press Enter |
Now type
10 .eql?10 Press Enter |
| Highlight true | We get the output as true |
| 10 != 10<<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
10 < 5 |
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
12 <= 12 << Press 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
3 <=> 3 << Press 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
4 <=> 3 << 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 <=> 7 << 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 <pause> |
| Slide11
Assignment |
As an assignment
Solve the following examples using irb and check the output
|
| <<Pause>>
This brings us to the end of this Spoken Tutorial. Let's summarize | |
| Slide 12
Summary |
In this tutorial we have learnt about
|
| 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 this is Anjana Nair signing off Thank you |
