Question

Alright, so this is the exercise:

Define a class named student,
containing three grades of students.
The class will have a function that
calculates the grades average. Now,
define a class named student1 which
will be derived from student and will
add a function to calculate the sum of
the grades.In the Main program, define
a student variable and object of type
student1. Perform placement of the
object to variable and run the
function of student1.

Note: This is not homework, I’m learning this my own.
This is the code:

class Student
{
    protected int grade1, grade2, grade3;
    public Student(int grade1, int grade2, int grade3)
    {
        this.grade1 = grade1;
        this.grade2 = grade2;
        this.grade3 = grade3;
    }
    public double Average()
    {
        return (grade1 + grade2 + grade3) / 3;
    }
}
class Student1 : Student
{
    public Student1(int grade1, int grade2, int grade3)
        : base(grade1, grade2, grade3)
    {
    }
    public double Sum()
    {
        return grade1 + grade2 + grade3;
    }
}
class Program
{
    static void Main(string[] args)
    {
    }
}

I don’t really know what to do in the main class, how do I perform this placement and also, I wanted to know what’s the benefit of doing it, let me know if I have mistakes so far, thanks alot.

Answer 1

OK: I guess this is what they’re looking for, although the english is a little ropey:

1) Declare student variable

 Student s;

2) Declare Student1 object

 Student1 s1 = new Student1(1,2,3);

3) Perform placement of object to variable:

s = s1;

4) Run the function (Note you’ll have to cast s to Student1 type to access the Type specific function Sum)

Console.WriteLine(((Student1)s).Sum());