We have to calculate the percentage of marks obtained in three subjects (each out of 100) by student A and in four subjects (each out of 100) by student B. Create an abstract class "Marks" with an abstract method "getPercentage". It is inherited by two other classes "A" and "B"; each having a method with the same name which returns the percentage of the students. The constructor of student A takes the marks in three subjects as its parameters and the marks in four subjects as its parameters for student B. Create an object for each of the two classes and print the percentage of marks for both the students.

Source Code..

 //@author Java_Programs

abstract class Marks {

    public abstract float getPercentage();

}

 

class A extends Marks {

    private float marks1, marks2, marks3;

 

    public A(float m1, float m2, float m3) {

        marks1 = m1;

        marks2 = m2;

        marks3 = m3;

    }

 

    public float getPercentage() {

        return ((marks1 + marks2 + marks3) / 300) * 100;

    }

}

 

class B extends Marks {

    private float marks1, marks2, marks3, marks4;

 

    public B(float m1, float m2, float m3, float m4) {

        marks1 = m1;

        marks2 = m2;

        marks3 = m3;

        marks4 = m4;

    }

 

    public float getPercentage() {

        return ((marks1 + marks2 + marks3 + marks4) / 400) * 100;

    }

}

 

public class Main {

    public static void main(String[] args) {

        A studentA = new A(80, 85, 90);

        B studentB = new B(75, 80, 85, 90);

        System.out.println("Percentage of marks for student A: " + studentA.getPercentage() + "%");

        System.out.println("Percentage of marks for student B: " + studentB.getPercentage() + "%");

    }

}

 

we have created an abstract class Marks with an abstract method getPercentage. We have also created two concrete classes A and B which inherit the Marks class and implement the getPercentage method.

 

The A class has a constructor that takes the marks obtained by student A in three subjects as its parameters. The getPercentage method of the A class calculates the percentage of marks obtained by student A in these three subjects and returns it.

 

Similarly, the B class has a constructor that takes the marks obtained by student B in four subjects as its parameters. The getPercentage method of the B class calculates the percentage of marks obtained by student B in these four subjects and returns it.

 

Finally, in the Main class, we create objects studentA and studentB of the A and B classes, respectively. We then call the getPercentage method on both objects and print the percentage of marks obtained by each student to the console.

 

When we run the program, we get the following output:

Percentage of marks for student A: 85.0%

Percentage of marks for student B: 82.5%

As we can see from the output, the getPercentage method of the A class correctly calculates the percentage of marks obtained by student A in three subjects, and the getPercentage method of the B class correctly calculates the percentage of marks obtained by student B in four subjects.