C++ In a Nutshell

<bitset>

The <bitset> header declares a single class template, bitset, and some related functions. A bitset is a fixed-size sequence of bits. The bitwise operators (&, |, ^, etc.) are overloaded to work with bitsets in the usual manner, and you can refer to individual bits by index.

The Boost project has a class template for a bit sequence that can change size at runtime. See Appendix B for information about Boost.