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class Base(): """ My base class """ __nb_instances = 0 def __init__(self): Base.__nb_instances += 1 self.id = Base.__nb_instancesclass User(Base): """ My User class """ def __init__(self): super().__init__()u = User()print(u.id)

Question

class Base(): """ My base class """ __nb_instances = 0 def init(self): Base.__nb_instances += 1 self.id = Base.__nb_instancesclass User(Base): """ My User class """ def init(self): super().init()u = User()print(u.id)

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Solution

The given code is written in Python. It defines two classes: Base and User. User is a subclass of Base.

Here's a step-by-step explanation of what the code does:

  1. The Base class is defined with a private class variable __nb_instances which is initially set to 0. This variable is used to keep track of the number of instances of the Base class.

  2. The Base class has an __init__ method (which is a special method in Python classes, known as a constructor). This method is called when an instance of the class is created. In this method, __nb_instances is incremented by 1 and the instance variable id is set to the current value of __nb_instances.

  3. The User class is defined as a subclass of Base. It also has an __init__ method. In this method, the __init__ method of the superclass (Base) is called using the super() function. This means that when a User instance is created, it will also increment __nb_instances and set its id.

  4. An instance of the User class is created and assigned to the variable u.

  5. The id of u is printed. Since u is the first instance of Base (through User), its id is 1.

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Similar Questions

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