What does the question mark and the colon (?: ternary operator) mean in objective-c?

Question

What does this line of code mean?

label.frame = (inPseudoEditMode) ? kLabelIndentedRect : kLabelRect;

The ? and :

Answer 1

Building on Barry Wark's excellent explanation...

What is so important about the ternary operator is that it can be used in places that an if-else cannot. ie: Inside a condition or method parameter.

[NSString stringWithFormat: @"Status: %@", (statusBool ? @"Approved" : @"Rejected")]

...which is a great use for preprocessor constants:

// in your pch file...
#define statusString (statusBool ? @"Approved" : @"Rejected")

// in your m file...
[NSString stringWithFormat: @"Status: %@", statusString]

This saves you from having to use and release local variables in if-else patterns. FTW!