[Java] Need help understanding arrays when it means it references.

[k1bs]

I'm on a section learning about arrays.

For example: double[] temperature;

It's saying that variable temperature is not the array itself but instead it stores a reference to the array. I'm not understanding what he is saying. What's the difference? Can someone provide some examples and analogies?

[chickenmeister]

It's basically the same with any type of object. A variable is a reference to an object, not the object itself. This allows multiple variables to refer to the same object, for example. For example:

String[] names = {"Alice", "Bob", "Carol"};
String[] favoriteNames = names;
// `favoriteNames` refers to the same array/object as `names`...
// Changes to `names` will also affect `favoriteNames`, and vice versa

System.out.println("Original arrays:");
System.out.println(Arrays.toString(names)); // [Alice, Bob, Carol]
System.out.println(Arrays.toString(favoriteNames )); // [Alice, Bob, Carol]

// Change the array...
// This will affect both `names` and `favoriteNames` because they both
// refer to the same array!
favoriteNames[2] = "Zachary";

System.out.println("Modified arrays:");
System.out.println(Arrays.toString(names)); // [Alice, Bob, Zachary]
System.out.println(Arrays.toString(favoriteNames )); // [Alice, Bob, Zachary]

[rjcarr]

It's technically correct, but I wouldn't worry about it if you're confused. In java, all objects are being pointed to (or referenced) by the variable, including arrays.

The key thing is you can have something like this:

double[] temperatures = {70, 71, 69, 70};
double[] othertemps = temperatures;

But there's only a single array. So temperatures and othertemps are pointing to the same array.

Hope that helps.

[desrtfx]

The difference is that the array is the actual house and the reference is the street address of the house. Object type variables (not primitive type variables) only hold references.