The best Ruby classes and objects Tutorial In 2024, In this tutorial you can learn Defining a class in Ruby,Ruby class variables,Examples,Creating objects usingnewmethods in Ruby,Custom method to create Ruby objects,Ruby class member functions,Simple Case Study,
Ruby is a perfect object-oriented programming language. Object-oriented programming language features include:
These features will be object-oriented Ruby were under discussion.
An object-oriented programming, classes and objects involved. Class is a blueprint for individual objects created. In object-oriented terms, your bicycle is an instance of the class bike.
In the vehicle, for example, it includes a wheel (wheels), HP (horsepower), oil or gas tank capacity (fuel or gas tank capacity). These properties formed the data members of the vehicle (Vehicle) class. With these attributes that you can distinguish one vehicle from another vehicle.
Vehicles can also contain a specific function, such as pause (halting), driving (driving), speeding (speeding). These functions forming the data members of the vehicle (Vehicle) class. Therefore, you can define the class as a combination of properties and functions.
Vehicle class defined as follows:
Class Vehicle { Number no_of_wheels Number horsepower Characters type_of_tank Number Capacity Function speeding { } Function driving { } Function halting { } }
By giving these data members assigned different values, you can create different instances of the class Vehicle. For example, an airplane with three wheels, 1,000 horsepower, fuel tank capacity of 100 liters. In the same way, a car with four wheels, 200 horsepower, a gas tank capacity of 25 liters.
In order to use Ruby object-oriented programming, you'll need to learn how to create objects and classes in Ruby.
In Ruby, class always begins with the keywordclass,followed by the name of the class. The first letter of the class name should be capitalized.Customerclass as follows:
class Customer end
You can use the keywordendto terminate a class. All the data members ofthe classare between the class definition and theendkeywords.
Ruby provides four types of variables:
Use a class variable @@ no_of_customers, you can determine the number of objects to be created, so you can determine the number of customers.
class Customer @@ No_of_customers = 0 end
Objects are instances of classes. You will now learn how to create objects of the class in Ruby. In Ruby, you can use the class method to create anewobject.
Newmethod is a unique approach, the predefined library in Ruby. new methods belong to theclassmethods.
The following example creates two objects cust1 class Customer and cust2:
cust1 = Customer. new cust2 = Customer. new
Here, cust1 and cust2 is the name of two objects. After the object name followed by an equal sign (=) after the equal sign followed by the class name, then the dot operator and the keywordnew.
You can pass parameters to thenewmethod, these parameters can be used to initialize the class variables.
When you wantnewmethod declaration with parameters, you need to create a class at the same time declare a methodinitialize.
initializemethod is a special type of method will be executed when thenewmethod is called with a parameter class.
The following example creates initialize method:
class Customer @@ No_of_customers = 0 def initialize (id, name, addr) @ Cust_id = id @ Cust_name = name @ Cust_addr = addr end end
In this example, you can declare withid, name, addr as theinitializemethod local variables.Here,def andendfor defining Ruby methodinitialize.In later chapters, you'll learn more details about the method.
In theinitializemethod, the values of these local variables to the instance variable @ cust_id, @ cust_name and @cust_addr. Here, the value of the local variable with the new method of delivery.
Now, you can create an object, as follows:
cust1 = Customer.new ( "1", "John", "Wisdom Apartments, Ludhiya") cust2 = Customer.new ( "2", "Poul", "New Empire road, Khandala")
In Ruby, functions are called methods. Eachclassmethod is based on the keyworddef,followed by a method name.
Method name is always lowercase letter.In Ruby, you can use the keywordendto end one way.
The following example defines a Ruby method:
class Sample def function statement 1 statement 2 end end
Here,statement 1 andstatement 2is part of a class Samplefunctionmethod within the body. These statements can be any valid Ruby statement. For example, we can use the methodputsto outputHello Ruby,as follows:
class Sample def hello puts "Hello Ruby!" end end
The following example creates an object of class Sample and callhellomethod:
#! / Usr / bin / ruby class Sample def hello puts "Hello Ruby!" end end # Use the above class to create an object object = Sample. New object.hello
This will produce the following results:
Hello Ruby!
If you want to do more exercises about classes and objects, there is a case study: