Difference between revisions of "Ruby/C2/Arithmetic-and-Relational-Operators/English-timed"

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|* Arithmetic Operators  
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| Arithmetic Operators  
  
 
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|* Operator Precedence  
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| Operator Precedence  
  
 
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|* Relational Operators.
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|Relational Operators.
  
 
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|  Here we are using:
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|  Here we are using: '''Ubuntu Linux '''version '''12.04''' , '''Ruby 1.9.3'''
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* '''Ubuntu Linux '''version '''12.04'''
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* '''Ruby 1.9.3'''
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|* '+' Addition, e.g. a+b.  
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|'+' Addition, e.g. a+b.  
  
 
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|* '-' Subtraction, e.g. a-b.  
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|  '-' Subtraction, e.g. a-b.  
  
 
|-
 
|-
 
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|* '/' Division, e.g. a/b.  
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| '/' Division, e.g. a/b.  
  
 
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|* '*' Multiplication, e.g. a*b.  
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| '*' Multiplication, e.g. a*b.  
  
 
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| 00:55
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|* '%' Modulus, e.g. a%b.  
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| '%' Modulus, e.g. a%b.  
  
 
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|* '**' Exponent,  e.g. a**b.  
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| '**' Exponent,  e.g. a**b.  
  
 
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|and press '''Enter'''.
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|and press '''Enter'''. We get the answer as 3.
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|  We get the answer as 3.
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|* ''' == Equals to''',  e.g. a==b  
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| ''' == Equals to''',  e.g. a==b  
  
 
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|* ''' dot eql question mark'''  e.g. a.eql?b  
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| ''' dot eql question mark'''  e.g. a.eql?b  
  
 
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|* '''!=  Not equals to'''  e.g.  '''a exclamation equals b'''  
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| '''!=  Not equals to'''  e.g.  '''a exclamation equals b'''  
  
 
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|  05:28
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|* '''< Less than'''  e.g. a < b  
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| '''< Less than'''  e.g. a < b  
  
 
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|  05:32
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|* '''> Greater than'''  e.g. a > b  
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| '''> Greater than'''  e.g. a > b  
  
 
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|* ''' <= Lesser than or equal to  e.g. a less than arrow equals b'''  
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| ''' <= Lesser than or equal to  e.g. a less than arrow equals b'''  
  
 
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|* ''' >= Greater than or equal to'''  e.g. a greater than arrow equals b  
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| ''' >= Greater than or equal to'''  e.g. a greater than arrow equals b  
  
 
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|* '''  <=> Combined comparison''' e.g. a less than arrow equal greater than arrow b.  
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| '''  <=> Combined comparison''' e.g. a less than arrow equal greater than arrow b.  
  
 
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|and press '''Enter'''.  
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|and press '''Enter'''. We get the output as "true".
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|We get the output as "true".
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|Let's try it out.  
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|Let's try it out. Now, type ''' 10 .eql?10''' and press '''Enter'''.
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| Now, type ''' 10 .eql?10''' and press '''Enter'''.
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|* Returns 0 if first operand equals second  
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| Returns 0 if first operand equals second  
  
 
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|* Returns 1 if first operand is greater than the second and  
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| Returns 1 if first operand is greater than the second and  
  
 
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|* Returns -1 if first operand is less than the second operand.  
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|Returns -1 if first operand is less than the second operand.  
  
 
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|and press '''Enter'''.
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|and press '''Enter'''.We get the output as 1  
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|We get the output as 1  
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|We get the output as -1
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|We get the output as -1. Since 4 is less than 7.  
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|since 4 is less than 7.  
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|* ''' 10 +  bracket 2 asterisk 5 bracket 8 slash 2'''
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|''' 10 +  bracket 2 asterisk 5 bracket 8 slash 2'''
  
 
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|* '''4 asterisk 5 slash 2 plus 7'''
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| '''4 asterisk 5 slash 2 plus 7'''
  
 
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|* Arithmetic Operators-  plus, minus, asterisk, slash standing for addition, subtraction, multiplication, division.  
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| Arithmetic Operators-  plus, minus, asterisk, slash standing for addition, subtraction, multiplication, division.  
  
 
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|* Operator Precedence  
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| Operator Precedence  
  
 
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|* Relational Operators  
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| Relational Operators  
  
 
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|* Conducts workshops using spoken tutorials.  
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| Conducts workshops using spoken tutorials.  
  
 
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|10:23
 
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|* Gives certificates to those who pass an online test.  
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| Gives certificates to those who pass an online test.  
  
 
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| 10:26
 
| 10:26
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|For more details, please write to:
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|For more details, please write to: contact@spoken-tutorial.org
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contact@spoken-tutorial.org
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|More information on this mission is available at:
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|More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
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spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
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Latest revision as of 12:11, 10 March 2017


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 the following arithmetic operators.
00:42 '+' Addition, e.g. a+b.
00:45 '-' Subtraction, e.g. a-b.
00:48 '/' Division, e.g. a/b.
00:51 '*' Multiplication, e.g. a*b.
00:55 '%' Modulus, e.g. a%b.
00:59 '**' Exponent, e.g. 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 the 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 asterisk (*) has higher precedence than the addition operator plus (+)
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 Let's see some more examples based on operator precedence.
03:47 Let's go back to the terminal and
03:50 press Crtl, 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 operation is performed first and then subtraction is performed.
04:20 Let's see another example.
04:22 Type: within brackets 10 plus 2 slash 4
04:29 and press Enter. 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 the slides.
04:54 Relational operators are also known as comparison operators.
04:59 Expressions using relational operators return boolean values.
05:04 Relational operators in Ruby are-
05:07 == Equals to, e.g. a==b
05:14 dot eql question mark e.g. a.eql?b
05:21 != Not equals to e.g. a exclamation equals b
05:28 < Less than e.g. a < b
05:32 > Greater than e.g. a > b
05:37 <= Lesser than or equal to e.g. a less than arrow equals b
05:44 >= Greater than or equal to e.g. a greater than arrow equals b
05:49 <=> Combined comparison e.g. 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 Let's try equals to operator.
06:11 So, type: 10 equals equals 10
06:16 and press Enter. We get the output as "true".
06:20 The .eql? opeartor is same as equals to operator.
06:24 Let's try it out. Now, type 10 .eql?10 and press Enter.
06:33 We get the output as "true".
06:35 Now, let's 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 Now, let us 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 the 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 comparison operator.
08:19 The combined comparison 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.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. 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 asterisk 5 bracket 8 slash 2
09:32 4 asterisk 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, asterisk, 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 summarizes 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

Devraj, PoojaMoolya, Pratik kamble, Sandhya.np14, Shruti arya

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