static void Main()
{
Course c = new Course("Angular", 15, 2000);
c.Print(); // Print() of Course
c = new OnlineCourse
("Python", "http://www.xyz.com/2343", 40, 5000);
c.Print(); // Print() of OnlineCourse
}
static void Main()
{
Course c1 = new Course("Angular", 15, 2000);
OnlineCourse c2 = new OnlineCourse
("Python", "http://www.xyz.com/2343", 40, 5000);
}