Strange foreach loop behavior

Question

There is an instance field:

private int[] arr = new int[42];

I use the code:

 for (int cell : arr) { cell = -1; }

I hoped that this code would fill the array with -1 elements. This did not happen. The array is still zeros.

Please explain why this happened. What code is the foreach loop equivalent in this case?

@UserName Of course you are wrong, a person adds -1 to it and the code compiles, how can it be read-only?
If objects were stored in the array, and not primitives, then their state could be changed.
@iramm because the objects of the Integer class are not mutable, you can take some class like class Test {int x;}, and change the x values in foreach, then the changes will be displayed in the array.
Schild probably wrote a little different, and what happened was the inaccuracy of the translation.

Sergey Sergey 5.364 one 6 15 · Accepted Answer · 2016-05-14T00:45:47

Because this cycle is equivalent to the following

 for(int i = 0; i < arr.length; i++) { int cell = arr[i]; // получили копию i-го элемента cell = -1; // изменили копию }

1 answer 1