Basic Quantity Constructor
lTo define a quantity, we need to give values to all three internal variables:
public class Quantity
{
É stuff you already saw É
 public Quantity(double Factor, OpenList Num, OpenList Denom)
  {
  this.Factor = Factor;
  this.Num    = Num;
  this.Denom  = Denom;
  }
É more stuff to come É
 }
Variables in red represent values in this Quantity.
Variables in green represent values local to this
constructor.
The latter go away when the constructor is left.