How does the range-based for work for plain arrays?

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It works for any expression whose type is an array. For example:

int (*arraypointer)[4] = new int[1][4]{{1, 2, 3, 4}};
for(int &n : *arraypointer)
  n *= 2;
delete [] arraypointer;

For a more detailed explanation, if the type of the expression passed to the right of : is an array type, then the loop iterates from ptr to ptr + size (ptr pointing to the first element of the array, size being the element count of the array).

This is in contrast to user defined types, which work by looking up begin and end as members if you pass a class object or (if there is no members called that way) non-member functions. Those functions will yield the begin and end iterators (pointing to directly after the last element and the begin of the sequence respectively).

This question clears up why that difference exists.

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