libcxx/test/std/containers/unord/unord.map/hash_function.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <unordered_map>
  10
  11 // template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
  12 //           class Alloc = allocator<pair<const Key, T>>>
  13 // class unordered_map
  14
  15 // hasher hash_function() const;
  16
  17 #include <unordered_map>
  18 #include <string>
  19 #include <cassert>
  20
  21 int main(int, char**) {
  22   typedef std::unordered_map<int, std::string> map_type;
  23   map_type m;
  24
  25   std::pair<map_type::iterator, bool> p = m.insert(map_type::value_type(1, "abc"));
  26
  27   const map_type& cm = m;
  28   assert(cm.hash_function()(p.first->first) == cm.hash_function()(1));
  29   assert(cm.hash_function()(1) == cm.hash_function()(p.first->first));
  30
  31   return 0;
  32 }