Polymorphism

What is polymorphism?

The ability to treat values, objects, or functions of different types in a uniform way while allowing different behaviors

What are the two main categories of polymorphism?

• Ad-hoc polymorphism

• Universal polymorphism

What are the two forms of ad-hoc polymorphism?

• Coercion

• Overloading

What is coercion polymorphism?

Automatic conversion from one type to another.

Example: int -> double or double -> int

What is overloading polymorphism?

Using the same function or operator name with different parameter lists

What are the two forms of universal polymorphism?

• Inclusion

• Parametric

What is inclusion polymorphism?

Using inheritance and virtual functions so different derived objects can be treated through a common base class

How is inclusion polymorphism commonly implemented?

Using base-class pointers or references that point to derived-class objects

What operator is commonly used to invoke late binding through a base-class pointer?

ptr->virtualFunction();

What is parametric polymorphism?

Polymorphism implemented using templates so the same code works with many types

What are the benefits of templates?

• Code reuse

• Type safety

• Less repetitive code

What is early binding (static binding)?

Function calls are resolved at compile time

What is late binding (dynamic dispatch)?

Function calls are resolved at runtime

Which polymorphism types use early binding?

• Coercion

• Overloading

• Parametric polymorphism

Which polymorphism type uses late binding?

Inclusion polymorphism