I don't understand -(void) add: (Fraction *) f;

[isaiasMac]

can anybody explain why use this:

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

for this:

numerator = numerator * denominator + denominator *  numerator;
denominator = denominator * denominator;

Please help me !!

    thank you !!

[skochan]

When you write just numerator or denominator you refer to the receiver's numerator and denominator.   Since we called the Fraction argument that is passed to the add: method f, you need to write f.numerator and f.denominator to refer to its numerator and denominator.

So when you write

Code: (Objective-C)

[fract1 add: fract2];

the receiver of the add: message is fract1, and the argument is fract2.  So in the add: method, numerator and denominator refer to fract1's (the receiver's) numerator and denominator, while f.numerator and f.denominator refer to fract2's (the argument's) numerator and denominator, respectively.

Cheers,

Steve

[isaiasMac]

thank you Mr. skochan

[GM3131]

This explanation was extremely helpful.  I was dazed at first but now I believe I understand 7.3 now.

Just getting started on this stuff, this Web site has been awesome in helping me understand things.

Ian