libcxx/test/std/containers/unord/unord.map/load_factor.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 // float load_factor() const
  16
  17 #include <unordered_map>
  18 #include <string>
  19 #include <cassert>
  20 #include <cmath>
  21 #include <cfloat>
  22 #include <iterator>
  23
  24 #include "test_macros.h"
  25 #include "min_allocator.h"
  26
  27 int main(int, char**)
  28 {
  29     {
  30         typedef std::unordered_map<int, std::string> C;
  31         typedef std::pair<int, std::string> P;
  32         P a[] =
  33         {
  34             P(10, "ten"),
  35             P(20, "twenty"),
  36             P(30, "thirty"),
  37             P(40, "forty"),
  38             P(50, "fifty"),
  39             P(60, "sixty"),
  40             P(70, "seventy"),
  41             P(80, "eighty"),
  42         };
  43         const C c(std::begin(a), std::end(a));
  44         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
  45     }
  46     {
  47         typedef std::unordered_map<int, std::string> C;
  48         const C c;
  49         assert(c.load_factor() == 0);
  50     }
  51 #if TEST_STD_VER >= 11
  52     {
  53         typedef std::unordered_map<int, std::string, std::hash<int>, std::equal_to<int>,
  54                             min_allocator<std::pair<const int, std::string>>> C;
  55         typedef std::pair<int, std::string> P;
  56         P a[] =
  57         {
  58             P(10, "ten"),
  59             P(20, "twenty"),
  60             P(30, "thirty"),
  61             P(40, "forty"),
  62             P(50, "fifty"),
  63             P(60, "sixty"),
  64             P(70, "seventy"),
  65             P(80, "eighty"),
  66         };
  67         const C c(std::begin(a), std::end(a));
  68         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
  69     }
  70     {
  71         typedef std::unordered_map<int, std::string, std::hash<int>, std::equal_to<int>,
  72                             min_allocator<std::pair<const int, std::string>>> C;
  73         const C c;
  74         assert(c.load_factor() == 0);
  75     }
  76 #endif
  77
  78   return 0;
  79 }