attr_accessor is a Ruby language method used to create getter and setter methods for instance variables.
For example, if you have an instance variable @name, you can use attr_accessor to create getter and setter methods for it:
class Person
attr_accessor :name
end
person = Person.new
person.name = “John”
puts person.name # => “John
Classes and IDs are both used to identify elements in HTML documents. The main difference between them is that a class can be used to identify multiple elements, while an ID can only be used to identify one element.
Classes:
Classes are used to identify a group of elements that share the same characteristics. For example, if you wanted to style all
IDs:
IDs are used to identify a single element on a page. For example, if you wanted to style a specific
A class is a blueprint for creating objects, while a module is a collection of methods and constants that can be used by other classes.
For example, a class might be used to create objects that represent a car, such as a Ford Mustang. The class would define the attributes of the car, such as the make, model, and color.
A module, on the other hand, might contain methods for calculating fuel efficiency or calculating the cost of repairs. These methods could be used by any class, not just the car class.
A constructor is a special type of method that is used to create an instance of a class. It is called when an object of a class is created and has the same name as the class. A constructor does not have a return type and is used to initialize the state of an object.
Example:
public class Car {
private String make;
private String model;
// Constructor
public Car(String make, String model) {
this.make = make;
this.model = model;
}
}
A method is an ordinary subroutine that is used to perform a specific task. It is declared with a return type and a name, and can take arguments. It is called on an instance of a class and can return a value.
Example:
public class Car {
private String make;
private String model;
// Method
public String getMake() {
return make;
}
}
A Puppet class is a reusable block of Puppet code that can be used to define a set of related resources. It is used to create a group of related resources that can be easily managed and configured.
For example, a Puppet class could be used to define a web server with Apache, MySQL, and PHP installed. The class could define the installation of Apache, MySQL, and PHP, as well as the configuration of the web server. This class could then be used to deploy web servers in multiple environments with minimal effort.
An interface is a collection of abstract methods and constants that form a common set of base rules for a class to follow. An interface does not contain any implementation code, and it cannot be instantiated. An example of an interface might be a Comparable interface which defines the compareTo() method.
An abstract class is a class that contains both abstract methods (methods without an implementation) and concrete methods (methods with an implementation). An abstract class can be instantiated, and it is often used as a base class from which other classes can inherit. An example of an abstract class might be an Animal class which defines the abstract method makeSound() and the concrete method eat().
A constructor is a special type of method that is used to create an instance of an object. It is invoked when an instance of the object is created and it is used to set up the initial state of the object.
A method is a block of code that performs a specific task and is associated with an object. It is invoked by calling the method on the object.
Example:
Constructor:
public class Car {
private String make;
private String model;
public Car(String make, String model) {
this.make = make;
this.model = model;
}
}
Method:
public class Car {
private String make;
private String model;
public void setMake(String make) {
this.make = make;
}
public void setModel(String model) {
this.model = model;
}
}
A class method is a method that is defined in a class and can be called directly from the class without having to create an instance of the class first. An example of a class method is the __init__() method in Python.
An instance method is a method that is defined in a class and can only be called on an instance of the class. An example of an instance method is the __str__() method in Python.
Vaibhav Kothia