We say that if an object quacks like a duck, swims like a duck, eats like a duck or in short, acts like a duck, that object is a duck.

Let us see an example to implement thisExplanation

In line 13, the type of animal is not defined in the definition of the method Sound.

Type of animal is determined when the method is called, so it does not matter which object type you are passing as a parameter in the Sound() method, what matters is that the Speak() method should be defined in all the classes whose objects are passed in the Sound() method.

We can use any property or method of animal in the AnimalSound class as long as it is declared in that class.

Conclusion

Now coming back to why it is called Duck typing: So, if a bird speaks like a duck, swims like a duck, and eats like a duck, that bird is a duck.

Similarly, in the above example, the animal object does not matter in the definition of the Sound method as long as it has the associated behavior, Speak(), defined in the object’s class definition. In layman terms, since both the animals, dog and cats, can speak like animals, they both are animals. This is how we have achieved polymorphism without inheritance.: