Inheritance: Three Types Of Methods Explained

In inheritance, their are three types of methods that can exist when W

In inheritance, there are three types of methods that can exist when we compare methods in parent and child classes: 1. Methods that can exist in parent and not in child [child can then REUSE those methods from the parent class] 2. Methods that can exist in the child class and not the parent [Child then EXTEND the use in parent] and those methods can be used from the child class only 3. Methods with the exact same signature that can exist in both parent and child classes [This is an example of Overriding].

Create three classes: Student [ parent], GraduateStudent [ child ] and client to demo the three types of methods described earlier [i.e., at least one example for each]. The demo of the three types is expected to be shown in the client class.

This time I will check on the SEMANTICS of your examples where you need to mockup realistic examples. If you need to create other classes to help in showing your examples that is fine.

Paper For Above instruction

The concept of inheritance in object-oriented programming (OOP) allows subclasses to inherit properties and behaviors from a parent class, facilitating code reuse, modularity, and clarity. Understanding the types of methods involved in inheritance—methods that are inherited, extended, or overridden—is fundamental in designing robust and flexible classes. This paper explores these three types of methods through concrete, realistic examples using a Student hierarchy, illustrating how different method relationships operate in practice.

In Java, for example, methods in a parent class can be designed for reuse, extension, or overriding in subclasses. The first type involves methods present solely in the parent class—these can be inherited and reused by the child class without modification. For instance, a method calculating the average grade in a Student class may be inherited by GraduateStudent but left unchanged. This promotes code reuse and consistency across related classes.

The second type involves methods exclusive to the child class. These methods extend the functionality of the parent class and are not defined in the parent. An example is a method in GraduateStudent such as 'applyForResearchFunding,' which is relevant only to graduate students. These methods allow subclasses to expand on parent class capabilities, providing specialized functionalities relevant to the subclass context.

The third type involves methods with the same signature in both parent and child classes. This phenomenon, known as method overriding, allows the child class to provide a specific implementation of a method inherited from the parent, altering behavior as needed. An example is a method 'calculateTuition' in Student, which is overridden in GraduateStudent to account for different fee structures. Overriding is crucial for polymorphism, enabling objects to behave dynamically according to their actual class type.

To concretize these concepts, consider the following Java class hierarchy:

class Student {

public void displayDetails() {


System.out.println("Student details");


}


public double calculateTuition() {


return 5000;


}


}


class GraduateStudent extends Student {


public void displayResearch() {


System.out.println("Research details");


}


@Override


public double calculateTuition() {


return 7000; // overridden method


}


}

In this example, 'displayDetails' is inherited and reused (type 1). The 'displayResearch' method is unique to GraduateStudent (type 2). The 'calculateTuition' method exists in both classes with the same signature, demonstrating overriding (type 3). A client class can instantiate objects and demonstrate these relationships, invoking methods to showcase each type clearly and realistically.

In conclusion, understanding the semantic distinctions among inherited, extended, and overridden methods enables developers to design more effective class hierarchies. Proper use of each method type supports code reuse, specialization, and polymorphism, which are cornerstones of robust object-oriented software development. Through the realistic examples of Student and GraduateStudent classes, these concepts are made tangible, emphasizing their importance in practical programming.

References

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