How are methods with the private modifier implemented and what is their purpose in object-oriented programming?

In object-oriented programming, methods with the private modifier are intended for encapsulating the internal logic of a class. They are accessible only within the class itself and are not visible from outside, which allows hiding implementation details and protecting data from direct access.

In Python, there is no strict private modifier, but by convention, methods and attributes starting with a double underscore (__method) are considered private. This is implemented through a mechanism called name mangling, which alters the method's name to make external access more difficult.

Example:

class MyClass:
    def __private_method(self):
        print("This is a private method")

    def public_method(self):
        self.__private_method()  # call within the class

obj = MyClass()
obj.public_method()  # correct
# obj.__private_method()  # will raise an AttributeError

Thus, private methods serve to:

• Hide internal implementation
• Prevent accidental or incorrect usage
• Ensure control over the modification of the object's state