The word “polymorphism” means having many forms. In simple words, we can define polymorphism as the ability of a message to be displayed in more than one form.
A real-life example of polymorphism is a person who at the same time can have different characteristics. A man at the same time is a father, a husband, and an employee. So the same person exhibits different behavior in different situations. This is called polymorphism. Polymorphism is considered one of the important features of Object-Oriented Programming.
Types of Polymorphism
- Compile-time Polymorphism.
- Runtime Polymorphism.
1. Compile-Time Polymorphism
This type of polymorphism is achieved by function overloading or operator overloading.
A. Function Overloading
When there are multiple functions with the same name but different parameters, then the functions are said to be overloaded, hence this is known as Function Overloading. Functions can be overloaded by changing the number of arguments or/and changing the type of arguments. In simple terms, it is a feature of object-oriented programming providing many functions to have the same name but distinct parameters when numerous tasks are listed under one function name. There are certain Rules of Function Overloading that should be followed while overloading a function.
Below is the C++ program to show function overloading or compile-time polymorphism:
value of x is 7 value of x is 9.132 value of x and y is 85, 64
Explanation: In the above example, a single function named function func() acts differently in three different situations, which is a property of polymorphism.
To know more about this, you can refer to the article – Function Overloading in C++.
B. Operator Overloading
C++ has the ability to provide the operators with a special meaning for a data type, this ability is known as operator overloading. For example, we can make use of the addition operator (+) for string class to concatenate two strings. We know that the task of this operator is to add two operands. So a single operator ‘+’, when placed between integer operands, adds them and when placed between string operands, concatenates them.
Below is the C++ program to demonstrate operator overloading:
12 + i9
Explanation: In the above example, the operator ‘+’ is overloaded. Usually, this operator is used to add two numbers (integers or floating point numbers), but here the operator is made to perform the addition of two imaginary or complex numbers.
To know more about this one, refer to the article – Operator Overloading.
2. Runtime Polymorphism
This type of polymorphism is achieved by Function Overriding. Late binding and dynamic polymorphism are other names for runtime polymorphism. The function call is resolved at runtime in runtime polymorphism. In contrast, with compile time polymorphism, the compiler determines which function call to bind to the object after deducing it at runtime.
A. Function Overriding
Function Overriding occurs when a derived class has a definition for one of the member functions of the base class. That base function is said to be overridden.
Below is the C++ program to demonstrate function overriding:
print derived class show base class
A virtual function is a member function that is declared in the base class using the keyword virtual and is re-defined (Overridden) in the derived class.
Some Key Points About Virtual Functions:
- Virtual functions are Dynamic in nature.
- They are defined by inserting the keyword “virtual” inside a base class and are always declared with a base class and overridden in a child class
- A virtual function is called during Runtime
Below is the C++ program to demonstrate virtual function:
Called virtual Base Class function Called GFG_Base print function
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