Empty method name, what does this actually do?

Question

I\'m currently learning myself objective-c and iOS programming and found myself stuck with non-working code due to this subtle error for an hour. Consider the following code

Answer 1

A method declare like the one you posted is rare (and poor style, imo). Objective-C is supposed to be verbose. Methods break down like this:

1. First character: Either - or +. - means it is an instance method, + means it is a class method.
2. Value in parentheses: The return type of the method. In your example, the method returns an (NSString *).
3. The rest (before the curly braces) is the method name along with any parameters they take. You could have a name with no parameters, in which case the method name would not have a : in it. Such as - (void) reload; This would be a method that doesn't return a value and takes no parameters.
4. If your method takes parameters, they will be mixed into the method name and usually will declare the type (unlike your example). Such as - (NSString *) reverseString:(NSString *) stringToReverse; In this example your method name would be reverseString: it takes one parameter, an NSString* that will be called stringToReverse in the method definition.
5. Usually, if you see a : with no type it will be a case like - (float) addThreeValues::: This method returns a float and takes 3 parameters. This would be an appropriate definition because the three values don't matter what order they are provided because we are just adding them.