Constructors and Destructors in Objective-C?

Traditionally in languages like Java and C# a constructor is where you would perform your initializations. In Objective-C you would do so in the init method even though you create a convenience constructor. The convenience constructor as the name suggests is a shortcut so you don't have to write out two statements namely: alloc and init.

Prior to Automatic Reference Counting you would have to perform all your object deallocations in the dealloc method. Now thanks to ARC you no longer have to worry about manually deallocating objects. For the rare occasions that you do need to perform any manual housekeeping you can override the dealloc method but then do not forget to make a call to [super dealloc].

Here's a word of caution directly from the docs:

Even though ARC destroys instance variables automatically, there are still legitimate reasons to write a dealloc method, such as freeing non-retainable resources. Failing to call [super dealloc] in such a method is nearly always a bug. Sometimes, the object is simply trying to prevent itself from being destroyed, but dealloc is really far too late for the object to be raising such objections. Somewhat more legitimately, an object may have been pool-allocated and should not be deallocated with free; for now, this can only be supported with a dealloc implementation outside of ARC. Such an implementation must be very careful to do all the other work that NSObject‘s dealloc would, which is outside the scope of this document to describe.