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

{| border=1

{| border=1

|| '''Narration'''

|| '''Narration'''

|-

|-

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

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

|-

|-

| In this tutorial we will learn about  

| In this tutorial we will learn about  

|-

|-

| Arithmetic Operators  

| Arithmetic Operators  

|-

|-

| Operator Precedence  

| Operator Precedence  

|-

|-

| Relational Operators

| Relational Operators

|-

|-

|  Here we are using ''Ubuntu Linux '''version 12.04  '''Ruby''' 1.9.3

|  Here we are using ''Ubuntu Linux '''version 12.04  '''Ruby''' 1.9.3

|-

|-

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

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

|-

|-

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

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

|-

|-

|If not, for relevant tutorials, please visit our website  

|If not, for relevant tutorials, please visit our website  

|-

|-

|Now let us learn about arithmetic operators.  

|Now let us learn about arithmetic operators.  

|-

|-

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

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

|-

|-

|'''+'''Addition: eg. a+b.  

|'''+'''Addition: eg. a+b.  

|-

|-

|  - Subtraction: eg. a-b.  

|  - Subtraction: eg. a-b.  

|-

|-

|'''/''' Division: eg. a/b.  

|'''/''' Division: eg. a/b.  

|-

|-

|* Multiplication: eg. a*b.  

|* Multiplication: eg. a*b.  

|-

|-

| % Modulus: eg. a%b.  

| % Modulus: eg. a%b.  

|-

|-

|** Exponent : eg a**b  

|** Exponent : eg a**b  

|-

|-

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

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

|-

|-

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

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

|-

|-

|A terminal window appears on your screen.  

|A terminal window appears on your screen.  

|-

|-

| Type ''' irb''' and press Enter to launch the ''' interactive Ruby. '''

| Type ''' irb''' and press Enter to launch the ''' interactive Ruby. '''

|-

|-

|Type 10 plus 20 and press '''Enter. '''

|Type 10 plus 20 and press '''Enter. '''

|-

|-

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

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

|-

|-

|Similarly the subtraction and multiplication operations can be performed.  

|Similarly the subtraction and multiplication operations can be performed.  

|-

|-

|  Let us try the division operator.  

|  Let us try the division operator.  

|-

|-

|Type '''10 slash 4'''

|Type '''10 slash 4'''

|-

|-

| and press '''Enter. '''

| and press '''Enter. '''

|-

|-

| Here you can see the result is truncated to the nearest whole number which is 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'''

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

|-

|-

|Type '''10.0 slash 4'''

|Type '''10.0 slash 4'''

|-

|-

|and press '''Enter. '''

|and press '''Enter. '''

|-

|-

|  Now we get the result as 2.5

|  Now we get the result as 2.5

|-

|-

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

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

|-

|-

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

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

|-

|-

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

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

|-

|-

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

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

|-

|-

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

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

|-

|-

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

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

|-

|-

| So we get the output as 32.

| So we get the output as 32.

|-

|-

|Next, let us learn about operator precedence.  

|Next, let us learn about operator precedence.  

|-

|-

| When several operations occur in a mathematical expression,  

| When several operations occur in a mathematical expression,  

|-

|-

| each part is evaluated  

| each part is evaluated  

|-

|-

|and resolved in a predetermined order called '''operator precedence'''.  

|and resolved in a predetermined order called '''operator precedence'''.  

|-

|-

|  This means that the operator which has ''' highest priority''' is executed first.  

|  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.  

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

|-

|-

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

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

|-

|-

|  For example ''' 3 + 4 * 5 ''' returns 23 and not 35  

|  For example ''' 3 + 4 * 5 ''' returns 23 and not 35  

|-

|-

|The multiplication operator (*) has higher precedence than the addition operator (+)  

|The multiplication operator (*) has higher precedence than the addition operator (+)  

|-

|-

|  and thus will be evaluated first.  

|  and thus will be evaluated first.  

|-

|-

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

|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.  

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

|-

|-

|  Let's go back to the terminal.  

|  Let's go back to the terminal.  

|-

|-

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

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

|-

|-

|  Now type '''7 minus 2 multiply by 3 '''

|  Now type '''7 minus 2 multiply by 3 '''

|-

|-

|  and press '''Enter '''

|  and press '''Enter '''

|-

|-

|  We get the answer as 1.

|  We get the answer as 1.

|-

|-

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

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

|-

|-

|So the multiplication opertion is performed first and then subtraction is performed.  

|So the multiplication opertion is performed first and then subtraction is performed.  

|-

|-

|  Lets us see an another example.  

|  Lets us see an another example.  

|-

|-

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

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

|-

|-

|and Press '''Enter '''

|and Press '''Enter '''

|-

|-

|  We get the answer as 3.

|  We get the answer as 3.

|-

|-

|In this case () bracket has the higher priority than  division (slash)

|In this case () bracket has the higher priority than  division (slash)

|-

|-

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

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

|-

|-

|  Then ''' division''' is performed.  

|  Then ''' division''' is performed.  

|-

|-

|  Now, let us learn about Relational Operators.  

|  Now, let us learn about Relational Operators.  

|-

|-

|Let's switch back to slides.  

|Let's switch back to slides.  

|-

|-

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

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

|-

|-

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

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

|-

|-

|Relation Operators in '''Ruby''' are  

|Relation Operators in '''Ruby''' are  

|-

|-

|''' == Equals to'''  Eg. '''a==b '''

|''' == Equals to'''  Eg. '''a==b '''

|-

|-

|  ''' dot eql question mark'''  Eg. '''a.eql?b '''

|  ''' dot eql question mark'''  Eg. '''a.eql?b '''

|-

|-

|!= ''' Not equals to'''  Eg. ''' a exclamation equal b'''  

|!= ''' Not equals to'''  Eg. ''' a exclamation equal b'''  

|-

|-

| ''' Less than  Eg. a < b'''  

| ''' Less than  Eg. a < b'''  

|-

|-

|'''Greater than  Eg. a > b'''  

|'''Greater than  Eg. a > b'''  

|-

|-

| ''' <= Lesser than or equal to  Eg.a less than arrow equal b'''  

| ''' <= Lesser than or equal to  Eg.a less than arrow equal b'''  

|-

|-

|''' >= Greater than or equal to  Eg.a greater than arrow equal b'''  

|''' >= Greater than or equal to  Eg.a greater than arrow equal b'''  

|-

|-

|'''  <=> Combined comparison Eg.a less than arrow equal greater than arrow b'''  

|'''  <=> Combined comparison Eg.a less than arrow equal greater than arrow b'''  

|-

|-

|  Now let us try some of these operators.  

|  Now let us try some of these operators.  

|-

|-

|Go to the terminal.  

|Go to the terminal.  

|-

|-

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

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

|-

|-

|  Lets us try ''' equals to''' operator.  

|  Lets us try ''' equals to''' operator.  

|-

|-

|So type ''' 10 equals equals 10 '''

|So type ''' 10 equals equals 10 '''

|-

|-

|and Press ''' Enter'''  

|and Press ''' Enter'''  

|-

|-

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

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

|-

|-

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

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

|-

|-

|Lets try it out  

|Lets try it out  

|-

|-

| Now type ''' 10 .eql?10''' and Press Enter

| Now type ''' 10 .eql?10''' and Press Enter

|-

|-

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

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

|-

|-

|Now lets try ''' not equal to''' operator.  

|Now lets try ''' not equal to''' operator.  

|-

|-

| Type ''' 10 not equal 10'''  

| Type ''' 10 not equal 10'''  

|-

|-

| And Press ''' Enter'''  

| And Press ''' Enter'''  

|-

|-

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

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

|-

|-

|This is because the two numbers are equal.  

|This is because the two numbers are equal.  

|-

|-

|Clear the ''' irb''' console by pressing '''Ctrl, L''' simultaneously.  

|Clear the ''' irb''' console by pressing '''Ctrl, L''' simultaneously.  

|-

|-

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

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

|-

|-

|Type ''' 10 less than 5''' and Press Enter

|Type ''' 10 less than 5''' and Press Enter

|-

|-

|  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'''

|-

|-

|otherwise it will return ''' false'''   

|otherwise it will return ''' false'''   

|-

|-

|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

|-

|-

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

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

|-

|-

| Type '''5 greater than 2'''

| Type '''5 greater than 2'''

|-

|-

|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 '''

|-

|-

|otherwise it will return '''false '''

|otherwise it will return '''false '''

|-

|-

|Press ''' Enter'''

|Press ''' Enter'''

|-

|-

| 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

|-

|-

|Clear the '''irb''' console by pressing ''' Ctrl, L''' simultaneously  

|Clear the '''irb''' console by pressing ''' Ctrl, L''' simultaneously  

|-

|-

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

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

|-

|-

|  Type '''12 less than equal  12 '''

|  Type '''12 less than equal  12 '''

|-

|-

|and Press '''Enter '''

|and Press '''Enter '''

   

   

|-

|-

| 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 second then it returns '''true'''

|-

|-

| otherwise it returns '''false '''

| otherwise it returns '''false '''

|-

|-

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

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

|-

|-

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

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

|-

|-

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

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

|-

|-

|The ''' combined comparision''' operator  

|The ''' combined comparision''' operator  

|-

|-

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

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

|-

|-

|Returns 1 if first operand is greater than the second and  

|Returns 1 if first operand is greater than the second and  

|-

|-

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

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

|-

|-

|Let's see how it works with an example  

|Let's see how it works with an example  

|-

|-

|Type '''3 less than equals greater than 3 '''

|Type '''3 less than equals greater than 3 '''

|-

|-

|And Press '''Enter '''

|And Press '''Enter '''

|-

|-

|We get the output as 0

|We get the output as 0

|-

|-

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

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

|-

|-

|Now, let's change one of the operands to 4

|Now, let's change one of the operands to 4

|-

|-

|Type '''4 less than equals greater than 3 '''

|Type '''4 less than equals greater than 3 '''

   

   

|-

|-

|And Press '''Enter '''

|And Press '''Enter '''

|-

|-

|We get the output as 1  

|We get the output as 1  

|-

|-

|Since 4 is greater than 3  

|Since 4 is greater than 3  

|-

|-

|Now, let's change this example again  

|Now, let's change this example again  

|-

|-

|Type '''4 less than equals greater than 7 '''

|Type '''4 less than equals greater than 7 '''

|-

|-

|And Press '''Enter '''

|And Press '''Enter '''

|-

|-

|We get the output as -1

|We get the output as -1

|-

|-

|Since 4 is less than 7  

|Since 4 is less than 7  

|-

|-

|As an assignment  

|As an assignment  

|-

|-

|Solve the following examples using irb and check the output  

|Solve the following examples using irb and check the output  

|-

|-

|''' 10 +  bracket 2 astreisk  5 bracket 8 slash 2'''

|''' 10 +  bracket 2 astreisk  5 bracket 8 slash 2'''

|-

|-

|'''4 astreisk 5 slash 2 plus 7'''

|'''4 astreisk 5 slash 2 plus 7'''

|-

|-

|Also, try arithmetic operators using methods  

|Also, try arithmetic operators using methods  

|-

|-

|This brings us to the end of this Spoken Tutorial.  

|This brings us to the end of this Spoken Tutorial.  

|-

|-

|Let's summarize  

|Let's summarize  

|-

|-

|In this tutorial we have learnt about  

|In this tutorial we have learnt about  

|-

|-

|Arithmetic Operators  plus minus astreisk slash standing for addition, subtraction, multiplication, division.  

|Arithmetic Operators  plus minus astreisk slash standing for addition, subtraction, multiplication, division.  

|-

|-

|Operator Precedence  

|Operator Precedence  

|-

|-

|Relational Operators  

|Relational Operators  

|-

|-

|using many examples  

|using many examples  

|-

|-

|  Watch the video available at the following link.

|  Watch the video available at the following link.

|-

|-

|It summarises the Spoken Tutorial project.

|It summarises the Spoken Tutorial project.

|-

|-

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

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

|-

|-

|  The Spoken Tutorial Project Team :

|  The Spoken Tutorial Project Team :

|-   

|-   

|Conducts workshops using spoken tutorials  

|Conducts workshops using spoken tutorials  

|-

|-

|Gives certificates to those who pass an online test  

|Gives certificates to those who pass an online test  

|-

|-

|For more details, please write to contact@spoken-tutorial.org

|For more details, please write to contact@spoken-tutorial.org

|-

|-

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

|  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.

|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

|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro

|-

|-

|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 Anjana Nair signing off  Thank you  

|And this is Anjana Nair signing off  Thank you  

|}

|}