Hi, all `gacap' is template library of "Generating All Combinations and Permutations". It's supper of std::next_permutation() and std::prev_permutation(). There's a old discussion: "[boost] [tr2]Add Combination against std::permutation. HELP!" http://lists.boost.org/Archives/boost/2006/09/110176.php I register a project in sf.net, http://gacap.wiki.sourceforge.net/. Some introductions are here. I put a .zip file in the vault, vault/Algorithms/gacap-0.0.4.zip. http://boost-consulting.com/vault/ It can also be downloaded from http://sourceforge.net/project/showfiles.php?group_id=209093 The package contains: gacap's header files doc/ example/ test/ doc/gacap.txt and doc/classes.txt are important introductions. I test it under three compilers, see doc/compile.txt. It's one year later. Thanks.