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// Copyright Daniel James 2005. Use, modification, and distribution are
// subject to 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/functional/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);
// 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());
}
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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