Difference between revisions of "Ruby/C3/Object-Oriented-Concept-in-Ruby/Kannada"

|| '''Narration'''

| '''Ruby''' ಯಲ್ಲಿ '''Object Oriented Concept''' (ಆಬ್ಜೆಕ್ಟ್ ಓರಿಯಂಟೆಡ್ ಕಾನ್ಸೆಪ್ಟ್) ಎಂಬ 'ಸ್ಪೋಕನ್ ಟ್ಯುಟೋರಿಯಲ್' ಗೆ ನಿಮಗೆ ಸ್ವಾಗತ.  

| ಈ ಟ್ಯುಟೋರಿಯಲ್ ನಲ್ಲಿ ನಾವು:  

|* 'Ruby'ಯಲ್ಲಿ 'ಮೆಥಡ್'ಗಳನ್ನು ಡಿಫೈನ್ ಮಾಡುವ ವಿಭಿನ್ನ ರೀತಿಗಳು ಇವುಗಳನ್ನು ಕಲಿಯುವೆವು.  

| 'ruby hyphen tutorial' ಮತ್ತು 'classes' ಡಿರೆಕ್ಟರೀಗಳಿಗೆ ಹೋಗೋಣ.  

|'Ruby' (ರೂಬಿ), ಒಂದು ಆಬ್ಜೆಕ್ಟ್ ಓರಿಯಂಟೆಡ್ ಭಾಷೆಯಾಗಿದೆ.  

| 'Ruby'ಯಲ್ಲಿ ವ್ಯಾಲ್ಯೂ, ಸ್ಟ್ರಿಂಗ್ ಅಥವಾ ಸಂಖ್ಯೆ ಎಲ್ಲವೂ ಆಬ್ಜೆಕ್ಟ್ ಗಳಾಗಿವೆ.

| 'ಕ್ಲಾಸ್' (class), ಸಂಬಂಧಿತ ಡೇಟಾ ಮತ್ತು ಫಂಕ್ಷನ್ ಗಳ ಒಂದು ಸಂಗ್ರಹವಾಗಿದೆ.

| ಇದು ಮಾಹಿತಿಯನ್ನು ವ್ಯವಸ್ಠಿತವಾಗಿ ಇಡಲು ಸಹಾಯಮಾಡುತ್ತದೆ.   

|''' class Product'''

|''' ruby code'''  

|'''end'''

| ಅನಂತರದ ಫೈಲ್ ನ ಹೆಸರುಗಳು, ಶಬ್ದಗಳನ್ನು ಬೇರ್ಪಡಿಸಲು 'ಅಂಡರ್ಸ್ಕೋರ್'ಅನ್ನು ಹೊಂದಿರುವುವು:  

| ಪ್ರಾಥಮಿಕ ಹಂತದ 'Ruby tutorials'ನಲ್ಲಿ ತೋರಿಸಿದಂತೆ 'gedit'ನಲ್ಲಿ ಒಂದು ಹೊಸ ಫೈಲನ್ನು ಕ್ರಿಯೇಟ್ ಮಾಡಿ.   

| ಈ ಉದಾಹರಣೆಯಲ್ಲಿ, ನಾನು 'Order' ಎಂಬ ಹೆಸರಿನ ಒಂದು 'class' (ಕ್ಲಾಸ್)ಅನ್ನು ಡಿಫೈನ್ ಮಾಡಿದ್ದೇನೆ.  

| ಈಗ, ಈ 'class'ಅನ್ನು ಉಪಯೋಗಿಸುವ ಸ್ವಲ್ಪ ಕೋಡ್ ಅನ್ನು ನಾವು ಸೇರಿಸೋಣ.  

| ಹೀಗೆ ಟೈಪ್ ಮಾಡಿ: '''puts Order dot instance underscore variables'''

| ಈ ಸಾಲಿನ ಮೊದಲು, 'puts' ಕೆಲವು ಅಕ್ಷರಗಳು ಹೊಸ ಪಂಕ್ತಿಗಾಗಿ ಸ್ಲ್ಯಾಶ್ 'n' ಅನ್ನು ಸೇರಿಸಿ.  

| '''ruby space class underscore definition dot rb'''  

| ಈಗ, ಹೀಗೆ ಟೈಪ್ ಮಾಡೋಣ: ''' puts Order dot class underscore variables'''  

| ಪಂಕ್ತಿಯ ಕೆಳಗೆ ಎಲ್ಲೆ ಗುರುತನ್ನು ಕಾಪಿ ಮತ್ತು ಪೇಸ್ಟ್ ಮಾಡಿ ಅದನ್ನು ಸೇವ್ ಮಾಡೋಣ.

| ಈಗ, ಟರ್ಮಿನಲ್ ಗೆ ಬದಲಾಯಿಸಿ ಫೈಲನ್ನು ಈ ಮೊದಲು ಮಾಡಿದಂತೆ ಎಕ್ಸೀಕ್ಯೂಟ್ ಮಾಡೋಣ.  

| 'ಆಬ್ಜೆಕ್ಟ್', 'ಕ್ಲಾಸ್'ನ ಒಂದು ಇನ್ಸ್ಟನ್ಸ್ ಆಗಿದೆ.

| ಎಂದರೆ, 'ಆಬ್ಜೆಕ್ಟ್'ಅನ್ನು ಕ್ಲಾಸ್ ನಿಂದ ಕ್ರಿಯೇಟ್ ಮಾಡಲಾಗುತ್ತದೆ.  

|'ಆಬ್ಜೆಕ್ಟ್', ಕ್ಲಾಸ್ ನಲ್ಲಿ ಡಿಫೈನ್ ಮಾಡಿದ ಗುಣಲಕ್ಷಣಗಳನ್ನು ಮತ್ತು ಮೆಥಡ್ ಗಳನ್ನು ಹೊಂದಿರುವುದು.  

| ಈ ಪ್ರಕ್ರಿಯೆಯನ್ನು 'ಆಬ್ಜೆಕ್ಟ್'ನ ಇನಿಶಿಯಲೈಜೇಶನ್ (initialization) ಎಂದು ಕರೆಯಲಾಗುತ್ತದೆ.  

|Now, let is look at what an ''' “initialize” method''' is.  

|An ''' initialize method''' is called at the time of 'ಆಬ್ಜೆಕ್ಟ್' '''object''' creation.  

| On calling '''new''' on an 'ಆಬ್ಜೆಕ್ಟ್' '''object''', we invoke the '''initialize method'''.  

|An '''initialize method''' may take a list of '''parameters.'''  

|Like other ''' Ruby methods''', it is preceded by the ''' “def” keyword.'''

|Let us look at an example.  

|Create a new file in '''gedit''' as shown in the basic level '''Ruby tutorials'''.

| And name it '''object undescore initialize dot rb'''.

| I have a working example of the'ಆಬ್ಜೆಕ್ಟ್' ''' object initialization''' code.  

| You can pause the tutorial and type the code as we go through it.   

|Here, I have defined a '''class''' called '''“Order” '''.

|Then I have defined the ''' initialize method''', with no '''argument.'''

| I have defined a ''''puts' method''' to display the message: “I have created an object”.

|Next, I have defined '''Order dot new'''.

|This will invoke the '''initialize method.'''

|Switch to the '''terminal''' and type:  

|'''ruby space object underscore initialize dot rb'''  

| and see the output.  

|You will see the message ''' “I have created an object”'''.  

|Now, let us go back to '''gedit''' and add an '''argument''' to the '''method.'''

|Let us modify the '''puts'''.   

|It should display the value of the ''' argument''' passed.  

| Next, let us type:  

|'''Order dot new(“I have created an object”).'''

|Here, we have given an argument to the new '''method'''.  

| This '''argument''' gets passed on to the '''initialize method.'''

|Switch to the ''' terminal''' and type:  

|'''ruby space object underscore initialize dot rb'''

|and see the output.  

|You will see the message ''' “I have created an object” ''' printed out.  

| Now, you would have understood what ''' object initialization''' means.  

|Recall that in Ruby, '''methods''' are the '''functions''' that a '''class''' performs.  

|Each '''method''' in a class is defined within the '''“def”'''  and '''“end”''' block.  

|A multiword  method-name is separated with an '''underscore.'''

|Some of the characters that can be appended to a '''method''' name are:  

| '?' (question-mark)  

|'=' (equal to).   

|Each of the characters add some meaning to the '''method.'''

|Let us look at some examples.  

|Create a new file in '''gedit''' as shown in the basic level '''Ruby tutorials'''.

|And name it: ''' class underscore methods dot rb'''.

|I have a working example of ''' class methods''' code.  

|You can pause the tutorial and type the code as we go through it.

|Here, I have defined a class named ''' “Animal”.'''

|Then I have two  methods- “breathe” and  “walk”.

|They are both defined with the “def” and  “end” keywords.  

|I have then initialized the ''' object Animal.'''

|I have assigned it to a variable called  “animal” with lowercase  “a”.  

|Then I have invoked the methods “breathe” and “walk” consecutively.  

|Now, let us '''execute''' the program.  

|Switch to the '''terminal''' and type:  

|''' ruby space class underscore methods dot rb '''

|and see the output.  

|You will notice the lines:

|'''“ I breathe” '''

|'''“I walk” '''

|printed out.  

|This is because you have invoked the two methods ''' “breathe” ''' and ''' “walk”. '''

|A '''“puts” ''' statement defined within these '''methods''' gives the results you see.  

|Next, let us look at how to create '''methods''' with a trailing '''question mark.'''

|Create a new file in '''gedit''' as shown in the basic level Ruby tutorials.

|And name it '''class underscore methods underscore with underscore trailing underscore characters dot rb'''.

|I have a working example of '''class methods''' with '''question mark''' code.  

|You can pause the tutorial and type the code as we go through it.  

|Here, I have taken the same '''class''' as before, as an example.  

|Here, the '''"breathe" method''' has a trailing question mark (?).  

|Such '''methods''' are generally used to return '''boolean values. '''

|This is based on the '''method''' naming convention of Ruby.  

|The '''method''' gets invoked by declaring '''animal dot breathe question-mark'''.

|Switch to the '''terminal''' and type:  

|'''ruby space class underscore methods underscore with underscore trailing underscore characters dot rb'''  and see the output.  

|You will notice the output as : ''' “true” '''

|Next, let us define another '''method''' called '''“walk”.'''

|Let us place an ''' equal-to''' sign ''' “=(value)”''' beside it.  

|Let us invoke this ''' method''' by calling ''' animal dot walk.'''

|Then let us execute this method.  

|Switch to the '''terminal''' and type:  

|'''ruby class underscore methods underscore with underscore trailing underscore characters dot rb'''

|and see the output.  

|It will give an ''' “undefined method” ''' error.  

|This is because the ''' equal to sign''' has another meaning.  

|It is used to assign a value to a ''' method.'''

|So, let us invoke the '''method''' a little differently this time.  

|Type: '''puts animal dot walk equal to “ hops” '''.

|Now, let us give it another try.  

|Switch to the ''' terminal''' and run the command like before and see the output.  

|You will notice that the word  '''“hops”''' get printed.  

|This demonstrates that the ''' equal to sign''' next to a method means assignment.

|Now you should be able to write your own '''methods. '''

|In this tutorial, we have learnt-  

|* How to declare '''classes '''

|* How to create '''objects''' of a ''' class'''

|* Different ways of defining '''methods''' in '''Ruby'''.  

|As an assignment:  

|Define a '''class Product'''

|Define '''methods''' that you can use to get values of “myvar” and set values for “myvar”.  

|To set values, define the '''method''' using “=” sign.  

|Instantiate the object of the '''class''' and set and get values using the above 2 methods.  

|  Watch the video available at the following link.

|It summarizes the Spoken Tutorial project.

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

|  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@spoken-tutorial.org

| '''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.

| This is Anjana Nair, signing off. Thank you.