correct answerIn order to restrict a variable of a class from inheriting to subclass, how variable should be declared?

To restrict a variable of a class from being inherited by a subclass, the variable should be declared as private. In object-oriented programming, particularly in languages like Java, C++, and Python, declaring a variable as private ensures that it cannot be accessed or modified directly by any subclass. This encapsulation principle protects the internal state of an object, allowing only the methods within the class to interact with the private variable.

Here’s a brief rundown of how this works in various languages:

1. Java: Use the private keyword.

   class Parent {
       private int restrictedVariable;
   }
   

2. C++: Use the private access specifier.

   class Parent {
   private:
       int restrictedVariable;
   };
   

3. Python: Use a single underscore for naming by convention, but it's important to note that this does not enforce privacy strictly. To indicate that a variable should not be accessed directly, you can also use double underscores to invoke name mangling.

   class Parent:
       def __init__(self):
           self.__restricted_variable = 0
   

Using private declarations effectively hides the variable from subclasses, maintaining a controlled interface for accessing it.