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Author Topic: Request for member in something not a structure or union (Read 14625 times)
MarkReid
Full Member
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Posts: 173






on: May 09, 2009, 03:32:15 PM

I get this as an error

Request for member 'denominator' in something not a structure or union

when I try and compile the following code.

Code: (Objective-C)
-(id) add: (id) f
{
// To add two fractions
// a/b + c/d = ((a*d) + (b*c)) / (b * d)

// result will store the result of the addition
id result = [[Fraction alloc] init];
int resultNum, resultDenom;

resultNum = numerator * f.denominator + denominator * f.numerator;
resultDenom = denominator * f.denominator;

[result setTo: resultNum over: resultDenom];
[result reduce];

return result;
}

When I stop using the dot syntax for f.denominator in favour of [f denominator] everything works fine. Can someone please help me understand why one is Ok and the other isn't?

I've used this code before but when I changed it to accept and return id objects it stopped working as it used to.

Thanks,

Mark
Last Edit: May 11, 2012, 08:06:26 AM by happyzhb Logged
skochan
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Hero Member
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Posts: 3114







Reply #1 on: May 09, 2009, 03:45:45 PM

The compiler is fussy when you use the dot operator on an id variable.  It doesn't like the fact that it doesn't know the object's type.  Stick to the [....] notation in such cases.

Cheers,

Steve
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MarkReid
Full Member
***
Posts: 173






Reply #2 on: May 09, 2009, 03:56:39 PM

Seems really weird but I guess it depends on how the compiler operates. Just a little quirk I'll need to get used to.

Thanks Steve.
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