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Pointers
If you have experience with C, C++, or Objective-C, you may know that these languages use pointers to refer to addresses in memory. A Swift constant or variable that refers to an instance of some reference type is similar to a pointer in C, but is not a direct pointer to an address in memory, and does not require you to write an asterisk (*) to indicate that you are creating a reference. Instead, these references are defined like any other constant or variable in Swift.
Here is the interpretation of "Pointers" from Apple doc. We all know that in C++ or Objective-c, the pointer point directly to the address in memory. But in Swift, Apple says A Swift constant or variable that refers to an instance of some reference type is similar to a pointer in C, but is not a direct pointer to an address in memory, it confuses me a lot. My question is what is the scene behind reference type, if it is not a direct pointer to an address in memory, where is it point to?
Any hint or clue will be greatly appreciated.
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Types in Swift fall into one of two categories: first, “value types”, where each instance keeps a unique copy of its data, usually defined as a struct, enum, or tuple. The second, “reference types”, where instances share a single copy of the data, and the type is usually defined as a class.
References are used to refer an existing variable in another name whereas pointers are used to store address of variable. References cannot have a null value assigned but pointer can. A reference variable can be referenced by pass by value whereas a pointer can be referenced by pass by reference.
References are usually preferred over pointers whenever you don't need "reseating". This usually means that references are most useful in a class's public interface. References typically appear on the skin of an object, and pointers on the inside.
Pointers: A pointer is a variable that holds the memory address of another variable. A pointer needs to be dereferenced with the * operator to access the memory location it points to. References: A reference variable is an alias, that is, another name for an already existing variable.
Classes are references types, so variables (var) and constants (let) that reference them are effectively pointers "behind the scenes". What the documentation is trying to get at is that this is hidden from the programmer. There are no pointer operators in Swift.
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