What Does the "?" Symbol Mean in Objective-C?

Question

I am learning Objective C for ios programming and ran into the following line of code in the getter method of a property of a card called suit:

-(NSString *)suit 
{
     return _suit ? _suit: @"?";
}

This is supposed to return "?" if the suit is nil but I'm not sure how this line works. What does the ? in "return _suit ?..." mean? How does this code function and how is it interpreted by the computer?

score 1 · Answer 1 · answered Jun 25 '13 at 18:48

1

That's the ternary operator. You can search the site to find out more.

Basically it means "if".

If _suit is not nil, return _suit, otherwise return @"?". (the "otherwise" is after the colon).

answered Jun 25 '13 at 18:48

nevan king

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score 0 · Answer 2 · answered Jun 25 '13 at 18:47

0

It it s ternary operator it is a short form of

if(_suit) {
   return _suit;
} else {
   return @"?";
}

answered Jun 25 '13 at 18:47

Matthew Graves

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Just to be clear: The ternary operator does not cause the function to return. It's only equivalent to that when used in a return statement. – Chuck Jun 25 '13 at 18:51
I'm aware of that, I was restating the expression: return _suit ? _suit: @"?"; – Matthew Graves Jun 25 '13 at 22:06

score 0 · Answer 3 · answered Jun 25 '13 at 18:48

0

? Is ternary operator which work very similar to if()...else...

(condition)?<value if true>:<value if false>

Read following:

Objective-C Tricks: #1 Ternary Operations
Objective-C ternary operator

answered Jun 25 '13 at 18:48

CRDave

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What Does the "?" Symbol Mean in Objective-C?

3 Answers3