Concept of Object Oriented Programs in Python
practice.

What is the use of duck typing?

What is the purpose of the constructor (__init__ method) in a class in Python?

What will be the output of the following Python code?

>>> class A:
	pass
>>> class B(A):
	pass
>>> obj=B()
>>> isinstance(obj,A)

What will be the output of the following Python code?

class Demo:
    def __init__(self):
        self.x = 1
    def change(self):
        self.x = 10
class Demo_derived(Demo):
    def change(self):
        self.x=self.x+1
        return self.x
def main():
    obj = Demo_derived()
    print(obj.change())
 
main()

What is the purpose of using abstraction in object-oriented programming?

What will be the output of the following Python code?

class A:
    def __str__(self):
        return '1'
class B(A):
    def __init__(self):
        super().__init__()
class C(B):
    def __init__(self):
        super().__init__()
def main():
    obj1 = B()
    obj2 = A()
    obj3 = C()
    print(obj1, obj2,obj3)
main()

What will be the output of the following Python code?

class Demo:
    def __init__(self):
        self.a = 1
        self.__b = 1
 
    def display(self):
        return self.__b
obj = Demo()
print(obj.a)

A class in which one or more methods are only implemented to raise an exception is called an abstract class.

How does inheritance promote code reusability in object-oriented programming?

What is the main advantage of using abstraction in object-oriented programming?

Which principle of OOP is related to creating new classes by extending existing classes?

What will be the output of the following Python code?

class A:
    def test(self):
        print("test of A called")
class B(A):
    def test(self):
        print("test of B called")
        super().test()  
class C(A):
    def test(self):
        print("test of C called")
        super().test()
class D(B,C):
    def test2(self):
        print("test of D called")      
obj=D()
obj.test()

Which of the following statements is true?

What is the purpose of the __str__ method in Python classes?

What will be the output of the following Python code?

class A:
    def one(self):
        return self.two()
 
    def two(self):
        return 'A'
 
class B(A):
    def two(self):
        return 'B'
obj1=A()
obj2=B()
print(obj1.two(),obj2.two())

What type of inheritance is illustrated in the following Python code?

class A():
    pass
class B():
    pass
class C(A,B):
    pass

What will be the output of the following Python code?

class A:
    def __init__(self):
        self._x = 5       
class B(A):
    def display(self):
        print(self._x)
def main():
    obj = B()
    obj.display()
main()

What will be the output of the following Python code?

class objects:
    def __init__(self):
        self.colour = None
        self._shape = "Circle" 
 
    def display(self, s):
        self._shape = s
obj=objects()
print(obj._objects_shape)

What will be the output of the following Python code?

class A:
    def __init__(self):
        self.__x = 1
class B(A):
    def display(self):
        print(self.__x)
def main():
    obj = B()
    obj.display()
main()

What will be the output of the following Python code?

class A:
    def __init__(self,x):
        self.x = x
    def count(self,x):
        self.x = self.x+1
class B(A):
    def __init__(self, y=0):
        A.__init__(self, 3)
        self.y = y
    def count(self):
        self.y += 1     
def main():
    obj = B()
    obj.count()
    print(obj.x, obj.y)
main()