memset() is bytewise, the only reason it works with -1 is all the bits are set in every bit width. 0xff repeated still ends up being -1 at int size (0xffffffff). But the byte 0x2a repeated will be something more like 0x2a2a2a2a, which is not equivalent to 0x2a.
I'd say the C++ was wrong/unclear.
If you want all the ints in your array to be a certain number, use std::fill.
If you want all their bits to be 1, use something like ~0 in the memset.
