Returns an array, initialized with enough memory to initially hold a given number of objects.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
The initial capacity of the new array.
An array initialized with enough memory to hold
num objects. The returned object might be different than the original receiver.
Mutable arrays expand as needed;
num simply establishes the object’s initial capacity.
This method is a designated initializer.