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

From Script | Spoken-Tutorial
Jump to: navigation, search
Line 37: Line 37:
 
|-
 
|-
 
|  00:28
 
|  00:28
−
|  You must also be familiar with '''irb.'''
+
|  You must also be familiar with ''''irb'.'''
  
 
|-
 
|-
Line 49: Line 49:
 
|-
 
|-
 
|  00:38
 
|  00:38
−
| '''Ruby''' has following arithmetic operators.  
+
| '''Ruby''' has the following arithmetic operators.  
  
 
|-
 
|-
Line 81: Line 81:
 
|-
 
|-
 
|  01:08
 
|  01:08
−
|  Open the terminal by pressing ''' Ctrl, Alt''' and ''' T '''keys simultaneously.  
+
|  Open the terminal by pressing ''' Ctrl, Alt''' and '''T '''keys simultaneously.  
  
 
|-
 
|-
 
| 01:14
 
| 01:14
−
|A terminal window appears on your screen.  
+
|A '''terminal window''' appears on your screen.  
  
 
|-
 
|-
 
| 01:17
 
| 01:17
−
| Type '''irb''' and press '''Enter''' to launch the '''interactive Ruby. '''
+
| Type "irb" and press '''Enter''' to launch the '''interactive Ruby. '''
  
 
|-
 
|-
Line 101: Line 101:
 
|-
 
|-
 
| 01:31
 
| 01:31
−
|Similarly the subtraction and multiplication operations can be performed.  
+
|Similarly, the subtraction and multiplication operations can be performed.  
  
 
|-
 
|-
Line 185: Line 185:
 
|-
 
|-
 
| 02:56
 
| 02:56
−
|  This means that the operator which has highest priority is executed first.  
+
|  This means that the operator which has the highest priority is executed first.  
  
 
|-
 
|-
Line 197: Line 197:
 
|-
 
|-
 
|  03:13
 
|  03:13
−
|  For example ''' 3 + 4 * 5 ''' returns 23 and not 35.  
+
|  For example, ''' 3 + 4 * 5 ''' returns 23 and not 35.  
  
 
|-
 
|-
 
| 03:23
 
| 03:23
−
|The multiplication operator (*) has higher precedence than the addition operator (+)  
+
|The multiplication operator asterisk (*) has higher precedence than the addition operator plus (+)  
  
 
|-
 
|-
Line 217: Line 217:
 
|-
 
|-
 
| 03:47
 
| 03:47
−
|  Let's go back to the terminal.
+
|  Let's go back to the terminal and
  
 
|-
 
|-
 
| 03:50
 
| 03:50
−
|Press ''' Crtl, L''' keys simultaneously to clear the '''irb''' console.  
+
|press ''' Crtl, L''' keys simultaneously to clear the '''irb''' console.  
  
 
|-
 
|-
Line 277: Line 277:
 
|-
 
|-
 
| 04:51
 
| 04:51
−
|Let's switch back to slides.  
+
|Let's switch back to the slides.  
  
 
|-
 
|-
Line 293: Line 293:
 
|-
 
|-
 
| 05:07
 
| 05:07
−
|* ''' == Equals to''',  e.g. '''a==b '''
+
|* ''' == Equals to''',  e.g. a==b  
  
 
|-
 
|-
 
|  05:14
 
|  05:14
−
|* ''' dot eql question mark'''  e.g. '''a.eql?b '''
+
|* ''' dot eql question mark'''  e.g. a.eql?b  
  
 
|-
 
|-
 
| 05:21
 
| 05:21
−
|* '''!=  Not equals to'''  e.g. ''' a exclamation equals b'''  
+
|* '''!=  Not equals to'''  e.g. '''a exclamation equals b'''  
  
 
|-
 
|-
 
|  05:28
 
|  05:28
−
|* ''' Less than  e.g. a < b'''
+
|* '''< Less than''' e.g. a < b  
  
 
|-
 
|-
 
|  05:32
 
|  05:32
−
|* '''Greater than  e.g. a > b'''
+
|* '''> Greater than''' e.g. a > b  
  
 
|-
 
|-
Line 317: Line 317:
 
|-
 
|-
 
| 05:44
 
| 05:44
−
|* ''' >= Greater than or equal to  e.g. a greater than arrow equals b'''
+
|* ''' >= Greater than or equal to''' e.g. a greater than arrow equals b  
  
 
|-
 
|-
 
| 05:49
 
| 05:49
−
|* '''  <=> Combined comparison e.g. a less than arrow equal greater than arrow b'''.  
+
|* '''  <=> Combined comparison''' e.g. a less than arrow equal greater than arrow b.  
  
 
|-
 
|-
Line 333: Line 333:
 
|-
 
|-
 
| 06:02
 
| 06:02
−
| Press ''' ctrl, L''' keys simultaneously to clear the '''irb''' console.  
+
| Press '''ctrl, L''' keys simultaneously to clear the '''irb''' console.  
  
 
|-
 
|-
Line 349: Line 349:
 
|-
 
|-
 
| 06:17
 
| 06:17
−
|We get the output as '''true.'''
+
|We get the output as "true".
  
 
|-
 
|-
 
| 06:20
 
| 06:20
−
|The ''' .eql?''' opeartor is same as ''' equals to''' operator.  
+
|The '''.eql?''' opeartor is same as ''' equals to''' operator.  
  
 
|-
 
|-
Line 365: Line 365:
 
|-
 
|-
 
|06:33
 
|06:33
−
|We get the output as '''true'''.
+
|We get the output as "true".
  
 
|-
 
|-
Line 381: Line 381:
 
|-
 
|-
 
| 06:46
 
| 06:46
−
|We get the output as ''' false.'''
+
|We get the output as "false".
  
 
|-
 
|-
Line 393: Line 393:
 
|-
 
|-
 
|  06:56
 
|  06:56
−
|  Let us now try ''' less than''' operator.  
+
|  Now, let us try ''' less than''' operator.  
  
 
|-
 
|-
Line 401: Line 401:
 
|-
 
|-
 
|  07:05
 
|  07:05
−
|  Here, if first operand is less than second then it will return '''true'''.
+
|  Here, if first operand is less than second then it will return "true".
  
 
|-
 
|-
 
| 07:10
 
| 07:10
−
|Otherwise, it will return '''false'''.   
+
|Otherwise, it will return "false".   
  
 
|-
 
|-
 
| 07:14
 
| 07:14
−
|We get the output as '''false''' because 10 is not less than 5.
+
|We get the output as "false" because 10 is not less than 5.
  
 
|-
 
|-
Line 420: Line 420:
 
|-
 
|-
 
| 07:26
 
| 07:26
−
|Here, if first operand is greater than second then it will return '''true''';
+
|Here, if first operand is greater than second then it will return "true";
  
 
|-
 
|-
 
| 07:31
 
| 07:31
−
|otherwise it will return '''false '''.
+
|otherwise it will return "false".
  
 
|-
 
|-
Line 432: Line 432:
 
|-
 
|-
 
| 07:36
 
| 07:36
−
| In this case, we get the output as '''true''' because 5 is indeed greater than 2.
+
| In this case, we get the output as "true" because 5 is indeed greater than 2.
  
 
|-
 
|-
Line 452: Line 452:
 
|-
 
|-
 
| 07:59
 
| 07:59
−
| Here, if first operand is less than or equal to second then it returns '''true''';
+
| Here, if first operand is less than or equal to the second then it returns "true";
  
 
|-
 
|-
 
| 08:04
 
| 08:04
−
| otherwise it returns '''false'''.
+
| otherwise it returns "false".
  
 
|-
 
|-
 
| 08:07
 
| 08:07
−
|We get the output as '''true''' because 12 is equal to 12.
+
|We get the output as "true" because 12 is equal to 12.
  
 
|-
 
|-
Line 476: Line 476:
 
|-
 
|-
 
| 08:21
 
| 08:21
−
|* Returns '''0''' if first operand equals second  
+
|* Returns 0 if first operand equals second  
  
 
|-
 
|-
Line 560: Line 560:
 
|-
 
|-
 
| 09:32
 
| 09:32
−
|* '''4 astreisk 5 slash 2 plus 7'''
+
|* '''4 asterisk 5 slash 2 plus 7'''
  
 
|-
 
|-
 
| 09:37
 
| 09:37
−
|* Also, try arithmetic operators using '''method'''s.  
+
| Also, try arithmetic operators using '''method'''s.  
  
 
|-
 
|-
Line 592: Line 592:
 
|-
 
|-
 
| 10:04
 
| 10:04
−
|using many examples.  
+
| using many examples.  
  
 
|-
 
|-
Line 600: Line 600:
 
|-
 
|-
 
| 10:10
 
| 10:10
−
|It summarize the Spoken Tutorial project.
+
|It summarizes the Spoken Tutorial project.
  
 
|-
 
|-

Revision as of 11:03, 19 November 2015


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.
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 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.
06:17 We get the output as "true".
06:20 The .eql? opeartor is same as equals to operator.
06:24 Let's try it out.
06:25 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.
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 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

Retrieved from "https://script.spoken-tutorial.org/index.php?title=Ruby/C2/Arithmetic-and-Relational-Operators/English-timed&oldid=24516"