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iOS +/ - Functions
- Thread starter Nnavick
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Class vs. instance methods. http://stackoverflow.com/questions/1053592/objective-c-class-vs-instance-methods
Covered in any general book on Objective-C/Cocoa/Cocoa Touch.
B
Covered in any general book on Objective-C/Cocoa/Cocoa Touch.
B
- sends the message (method) to a particular instance of your class (object), whereas the + sends the message to the class itself.
So an example of a class method (+) would be with NSString.
Code:
[NSString stringWithString:@"test"]; //this is a class methodAn example of an instance method (-) with NSString.
Code:
NSString *mystring = [[NSString alloc] initWithString:@"test"]; //creating my instance
[mystring compare:@"test"]; //this is an instance method
Last edited:
If you're coming from another programming language like C++ you can kind of think of the (+) functions as static member functions. And they are often used as a pseudo factory methods. For example a car class
vs
Code:
+ (id)carWithEngine:(Engine *)engine;vs
Code:
- (id)initWithEngine:(Engine *)engine;