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- // Copyright 2005-2009 Daniel James.
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- #include "./books.hpp"
- #include <boost/container_hash/hash.hpp>
- #include <cassert>
- // If std::unordered_set was available:
- //#include <unordered_set>
- // This example illustrates how to use boost::hash with a custom hash function.
- // For full details, see the tutorial.
- int main()
- {
- library::book knife(3458, "Zane Grey", "The Hash Knife Outfit");
- library::book dandelion(1354, "Paul J. Shanley", "Hash & Dandelion Greens");
- boost::hash<library::book> book_hasher;
- std::size_t knife_hash_value = book_hasher(knife);
- (void)knife_hash_value; // suppress unused variable warning
- // If std::unordered_set was available:
- //
- //std::unordered_set<library::book, boost::hash<library::book> > books;
- //books.insert(knife);
- //books.insert(library::book(2443, "Lindgren, Torgny", "Hash"));
- //books.insert(library::book(1953, "Snyder, Bernadette M.",
- // "Heavenly Hash: A Tasty Mix of a Mother's Meditations"));
- //assert(books.find(knife) != books.end());
- //assert(books.find(dandelion) == books.end());
- return 0;
- }
- namespace library
- {
- bool operator==(book const& a, book const& b)
- {
- return a.id == b.id;
- }
- std::size_t hash_value(book const& b)
- {
- boost::hash<int> hasher;
- return hasher(b.id);
- }
- }
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