typedef of array of typedefs of array
It's bool[4][2]You can verify it by static_assert:
static_assert(std::is_same<decltype(what_am_i), bool[4][2]>::value, "");static_assert(std::is_same<decltype(what_am_i), bool[2][4]>::value, ""); // failed
foo is an array with 2 elements of type bool, i.e. bool[2].
bar is an array with 4 elements of type foo, i.e. foo[4], each element is a bool[2].
Then what_am_i is bool[4][2].
In order to complete @Slardar Zhang's C++ answer for C:
It's bool[4][2].
You can verify it by either one of the following:
sizeof(what_am_i)/sizeof(*what_am_i) == 4sizeof(*what_am_i)/sizeof(**what_am_i) == 2