C++ Operator Overloading and Polymorphism

Posted on Feb 21, 2025 in Computers

Member Operators

Member operators are functions that define the behavior of operators when used with a class’s objects.

• Unary: One operand. Examples: ++i, --i, +value, -value. Declaration: return_type operator ++/--()
• Binary: Two operands. Examples: =, +=, -, *, /, ==, &&. Declaration: return_type operator symbol (type [identifier])
• Ternary: Three operands. Example: condition ? expression1 : expression2

Operators can be overloaded as:

• Member operators: Defined within the class, with access to the class representation.
• Helper Operators: Defined outside the class, without direct access to the class representation.

Bool Operator

Returns either true or false. The operator can check for validation; overload a bool operator, create conditions, and return a bool value.

Helper Functions

• Helper functions are defined outside of a class but support the operations of a class.
• They can simplify the implementation of member functions or provide additional functionality.
• Helper functions can be declared as friend functions to allow them to access the private members of a class.

Classes and Resources

• Classes are user-defined data types that encapsulate data and functions.
• Resources are any external entities that a class needs to manage (e.g., memory, file handles, network connections).
• A well-designed class should manage its resources efficiently and prevent resource leaks.

Input and Output Operators

• Input and output operators read and write objects of a class from and to streams.
• The stream insertion operator (<<) is used to write objects of a class to a stream.
• The stream extraction operator (>>) is used to read objects of a class from a stream.

Derived Classes

• Derived classes inherit properties and behaviors from a base class.
• A derived class can add new data members and member functions or override existing ones.

Functions in a Hierarchy

• A function hierarchy is a set of related functions sharing a common interface.
• In object-oriented programming, function hierarchies often implement polymorphism.

Virtual Functions

• Virtual functions can be overridden in derived classes.
• They are declared with the virtual keyword in the base class and implemented in the derived classes.
• Virtual functions enable polymorphism, allowing objects of derived classes to be treated as objects of the base class.

Abstract Base Classes

• An abstract base class is designed to be a base class for other classes.
• It contains one or more pure virtual functions, which have no implementation in the base class and must be implemented in derived classes.
• Abstract base classes often define interfaces that other classes must implement.

Derived Class with a Resource

• A derived class that manages a resource must ensure the resource is properly acquired, used, and released.
• Resource management can use techniques like reference counting, smart pointers, or RAII (Resource Acquisition Is Initialization).

Function Templates

• Function templates can be used with different data types.
• They are defined using a generic parameter list, specifying one or more template parameters.
• Template functions enable code reuse and simplify the implementation of algorithms working with different data types.

Input/Output Refinements

• Input/output refinements improve the input and output of objects.
• These can include overloading stream insertion and extraction operators, defining formatting functions, or using manipulators.

Polymorphism

• Polymorphism is the ability of objects of different classes to be treated as objects of a common base class.
• Polymorphism enables code reuse, simplifies code maintenance, and makes code more flexible and extensible.
• Polymorphism can be implemented using virtual functions, abstract base classes, and function hierarchies.