public ClassRoom(Pupil p1, Pupil p2, Pupil p3, Pupil p4)
: this(p1, p2, p3)
{
if (p4 == null)
throw new ArgumentNullException();
else
_pupils.Add(p4);
}
public ClassRoom(Pupil p1, Pupil p2)
{
if (p1 == null || p2 == null)
throw new ArgumentNullException();
else
{
_pupils.Add(p1);
_pupils.Add(p2);
}
}
