objective-c question

[Tamas Papp]

I'm writing a model that needs different demand curves (functions which
assign a quantity demanded to any given price.) I thought of writing a
"placeholder" class, DemandCurve, and subclasses like LinearDemandCurve,
PolynomialDemandCurve, etc. I define DemandCurve as 

@interface DemandCurve
{
}

- (double)getQuantity: (double)price;
@end

and then writing the subclasses. The classes which use a demand curve
would get a pointer to a DemandCurve subclass, but use it as a DemandCurve
because they only need the getQuantity function. How is this done in
Objective-C? I only have experience with C++.

Regards,

Tamas

P.S.: Does anybody know and URL for a good intoductory & reference page
for Objective C online?


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