Question

The class SalariedEmployee inherits both of the functions get_name and print_check (among other things) from the base class Employee, yet only the function declaration for the function print_check is given in the definition of the class SalariedEmployee. Why isn't the function declaration for the function get_name given in the definition of SalariedEmployee?

Short answer

Inheritance allows a derived class to inherit properties and methods from the base class. The SalariedEmployee class inherits both get_name and print_check functions from the base class Employee. However, if the derived class wants to modify the behavior of an inherited method, it needs to provide a new definition for that method, which is called method overriding. In this case, the SalariedEmployee class overrides the print_check function with a new definition. On the other hand, the SalariedEmployee class doesn't require any modification to the get_name function. Since the behavior of the get_name function doesn't need to be modified, there is no need to provide a function declaration for it in the SalariedEmployee class, and it can directly use the inherited get_name function from the base Employee class.

Step-by-step solution

Inheritance is a mechanism in object-oriented programming that enables a new class to inherit properties and methods of an existing class. The new class is called a derived class or subclass, and the existing class is the base class or superclass. In this exercise, SalariedEmployee is a derived class and Employee is the base class. When a derived class is created, it automatically inherits the properties and methods of its base class. With this knowledge, let's look into the problem statement about why the function declaration for the function get_name is not given in the definition of SalariedEmployee. #Step 2: Understand the base class and its functions#

The base class Employee contains the functions get_name and print_check. These functions are part of the Employee class and will be automatically inherited by any classes that extend the Employee class. In this exercise, the SalariedEmployee class extends or inherits the Employee class, which means both functions, get_name and print_check, should be available in this derived class. #Step 3: Analyze why only the function declaration for print_check is given in the derived class#

When a derived class inherits a base class, it can modify or create new behaviors for the inherited properties and methods. If the derived class wants to modify the behavior of an inherited method, it must provide a new definition for that method in the derived class. This is called method overriding. In this exercise, the SalariedEmployee class wants to modify the behavior of the print_check function; therefore, its declaration is given in the SalariedEmployee class with a new definition. This new definition will match the specific behavior required for the SalariedEmployee instances. #Step 4: Clarify why the function declaration for get_name is not given in the derived class#

When a derived class doesn't need to modify the behavior of an inherited method, it can simply use the method provided by the base class without needing to include its own function declaration. In this case, the SalariedEmployee class doesn't require any modification to the get_name function, and hence, there is no need to provide the function declaration for get_name in the SalariedEmployee class. The instances of SalariedEmployee class can directly use the inherited get_name function from the Employee base class, and it will work as expected.

Key concepts

Inheritance

Inheritance is a pillar of Object-Oriented Programming (OOP) that allows a class to inherit the features (fields and methods) of another class. This is crucial as it promotes code reusability, allowing new classes to be easily constructed with already established behaviors. When you think about inheritance, imagine creating a new folder on your computer that automatically includes files from an existing folder. You can utilize these files, and even make new ones or change existing ones as needed.

In the context provided, the class `SalariedEmployee` inherits methods like `get_name` and `print_check` from the base class `Employee`. This means `SalariedEmployee` automatically has access to these methods without needing to redefine them.

Benefits of inheritance include:

• Reduces code redundancy
• Encourages code organization
• Facilitates future maintenance and updates

These benefits streamline software development by ensuring that you can evolve your code with the needs of your system without rewriting existing logic.

Method Overriding

Method overriding is another important concept in Object-Oriented Programming that occurs when a derived class modifies an existing method from its base class. Think of it as receiving a hand-me-down but deciding to tweak it to better suit your style.

This is useful when a specific behavior in the derived class needs to be implemented differently than what is defined in the base class. In our scenario, the `SalariedEmployee` class uses method overriding to redefine the `print_check` method. This new definition will adapt its behavior specifically for the needs of `SalariedEmployee`, possibly adding additional details like salary information when printing the check.

Key points about method overriding:

• Ensures that a derived class can implement specific behaviors
• A void completely changing all inherited methods if only some require adjustments
• Improves the flexibility and adaptability of class hierarchies

It’s a powerful tool for adapting inherited methods to meet new requirements without compromising the integrity of the original implementation.

Base Class

The base class, sometimes known as a superclass, serves as a blueprint from which other classes can derive properties and behaviors. It acts as the foundation of your class hierarchy, providing a common structure that can be extended.

In our example, `Employee` is the base class. This class might include properties such as employee name, ID, and fundamental methods like `get_name` and `print_check`. These properties and methods are those every employee, regardless of their particular job or position, would need.

Benefits of utilizing a base class include:

• Encourages a consistent and unified design
• Facilitates easier debugging and comprehension
• Promotes scalability in larger systems

A well-structured base class allows derived classes to easily inherit and customize behaviors, fostering efficient and scalable application development.

Derived Class

Derived classes, also known as subclasses, expand on a base class by adding new behaviors or modifying existing ones to suit specialized needs. Think of them as custom variations built upon a standard template.

Here, `SalariedEmployee` is a derived class of the `Employee` base class. It inherits general methods like `get_name`, while also being able to override or introduce new methods like its own version of `print_check`, which may include salary specifics relevant to salaried employees.

Characteristics of derived classes include:

• Inheritance of all accessible properties and methods from the base class
• Ability to introduce new attributes and methods specific to their own needs
• Capacity to override base class methods to fine-tune behaviors

Derived classes allow developers to build complex systems flexibly, enabling adaptation to specific roles or functionalities while maintaining a shared, cohesive foundation with their base class.