template <size_t N> class bitset;
boolelements, but optimized for space allocation: generally, each element occupies only one bit (which, on most systems, is eight times less than the smallest elemental type:
foo, the expression
fooaccesses its fourth bit, just like a regular array accesses its elements. But because no elemental type is a single bit in most C++ environments, the individual elements are accessed as special references type (see bitset::reference).
boolspecialization of vector (