Objective-C method calling with multiple arguments

Question

I know the method listed below takes in 2 arguments, card and atTop. Why is atTop repeated twice? I know addCard is the name of the function and this function returns a void where card is a variable of type Card* and I know atTop is of type BOOL, but why is atTop twice?

- (void)addCard: (Card *)card atTop:(BOOL)atTop;

the last atTop is a reference name to the value. for example it could have been - (void)addCard: (Card *)card atTop:(BOOL)myBool; and inside the function you would've accessed it by using myBool. — Adil Soomro
– Adil Soomro, Commented Feb 16, 2014 at 21:44

Merlevede · Accepted Answer · 2014-02-16 21:45:30Z

2

That's because the full name of the method is

- addCard:atTop:

So the first atTop is part of the function name, the second atTop is the name of the parameter (both are equal in this case just by conincidence, they can be different)

edited Feb 16, 2014 at 21:45

answered Feb 16, 2014 at 21:03

Merlevede

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4 Comments

baskInEminence Over a year ago

In Obj. C, all additional parameters must be associated with a name and a variable? For example, void(addCard): (Card *)card atTop:(BOOL)atTop numCards:(int)numCards? I'm used to C++ where we just have one function name and put in as many variables needed. Just wanted to make sure

bbum Over a year ago

@baskInEminence They don't have to be the same, no.

Merlevede Over a year ago

@baskInEminence What you say ("parameters must be associated with a name and a variable") is confusing, a parameter is 'materialized' in a variable, and a variable has a name to refer to it. You can even have a function called '- addCard:::' (without 'intermediate sub-names')

rmaddy Over a year ago

It's a method, not a function (there is a difference).

Avt · Accepted Answer · 2014-02-16 21:03:33Z

0

It is objective c notation.

(void)addCard: (Card *)card atTop:(BOOL)atTop;

Method name (selector) - "addCard:atTop:"

Parametr 1 type - "Card*" name - "card"

Parametr 2 type - "BOOL" name "atTop"

Return value - "void"

answered Feb 16, 2014 at 21:03

Avt

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