I think the problem is that Challenges is a NSManagedObject class and you need the designated initializer: initWithEntity:insertIntoManagedObjectContext: instead of Challenges *newChallenge = [[Challenges alloc] init]; Read More..
My solution is a quick fix, but I think is easier than what Apple purposes on the the Release Notes. For more information search for 19775924 http://adcdownload.apple.com//Developer_Tools/Xcode_6.3_beta_3/Xcode_6.3_beta_3_Release_Notes.pdf here. What Apple says is that you create an Objective-C file and extend it (having to add it to the header files and all) and it’s on “Known … Read more
Yes, that is prohibited. Just as otherwise you cannot declare variables of differing types in one declaration statement (edit: modulo the declarator modifiers that @MrLister mentions). You can declare structs for (struct { int a = 0; short b = 0; } d; d.a < 10; ++d.a, ++d.b ) {} C++03 code: for (struct { … Read more
It is an braced-init-list. A braced-init-list existed before std::initializer_list and is used to initialize aggregates. int arr[] = {1,2,3,4,5}; The above used a braced-init-list to initialize the array, no std::initializer_list is created. On the other hand when you do std::vector<int> foo = {1,2,3,4,5}; foo is not an aggregate so the braced-init-list is used to create … Read more
This: static { System.out.print(“x “); } is a static initialization block, and is called when the class is loaded. You can have as many of them in your class as you want, and they will be executed in order of their appearance (from top to bottom). This: { System.out.print(“y “); } is an initialization block, … Read more
Designated initialisers come in two flavours: 1) It provides a quick way of initialising specific elements in an array: int foo[10] = { [3] = 1, [5] = 2 }; will set all elements to foo to 0, other than index 3 which will be set to 1 and index 5 which will be set … Read more
In Ruby, what’s the relationship between ‘new‘ and ‘initialize‘? new typically calls initialize. The default implementation of new is something like: class Class def new(*args, &block) obj = allocate obj.initialize(*args, &block) # actually, this is obj.send(:initialize, …) because initialize is private obj end end But you can, of course, override it to do anything you … Read more
They are class methods, not static methods1. This specific type, creating autoreleased objects, can be referred to as “factory methods” (formerly also “convenience constructors”), and they are discussed in the Concepts in ObjC Guide. They go something like this: + (instancetype)whatsisWithThingummy: (Thingummy *)theThingummy { return [[self alloc] initWithThingummy:theThingummy]; } Where Whatsis is your class, and … Read more
There is no way. You need a default constructor for array members and it will be called, afterwards, you can do any initialization you want in the constructor.
Static initializers are useful as cletus mentioned and I use them in the same manner. If you have a static variable that is to be initialized when the class is loaded, then a static initializer is the way to go, especially as it allows you to do a complex initialization and still have the static … Read more