libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.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 // <algorithm>
  10
  11 // template<RandomAccessIterator Iter>
  12 //   requires ShuffleIterator<Iter>
  13 //   void
  14 //   random_shuffle(Iter first, Iter last);
  15
  16 // REQUIRES: c++03 || c++11 || c++14
  17 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
  18
  19 #include <algorithm>
  20 #include <array>
  21 #include <cassert>
  22
  23 #include "test_macros.h"
  24 #include "test_iterators.h"
  25
  26 template <class Iter>
  27 void
  28 test_with_iterator()
  29 {
  30   std::array<int, 0> empty = {};
  31   std::random_shuffle(Iter(empty.data()), Iter(empty.data()));
  32
  33   const int all_elements[] = {1, 2, 3, 4};
  34   int shuffled[]           = {1, 2, 3, 4};
  35   const unsigned size      = sizeof(all_elements) / sizeof(all_elements[0]);
  36
  37   std::random_shuffle(Iter(shuffled), Iter(shuffled + size));
  38   assert(std::is_permutation(shuffled, shuffled + size, all_elements));
  39
  40   std::random_shuffle(Iter(shuffled), Iter(shuffled + size));
  41   assert(std::is_permutation(shuffled, shuffled + size, all_elements));
  42 }
  43
  44
  45 int main(int, char**)
  46 {
  47     int ia[]  = {1, 2, 3, 4};
  48     int ia1[] = {1, 4, 3, 2};
  49     int ia2[] = {4, 1, 2, 3};
  50     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
  51
  52     std::random_shuffle(ia, ia+sa);
  53     LIBCPP_ASSERT(std::equal(ia, ia+sa, ia1));
  54     assert(std::is_permutation(ia, ia+sa, ia1));
  55
  56     std::random_shuffle(ia, ia+sa);
  57     LIBCPP_ASSERT(std::equal(ia, ia+sa, ia2));
  58     assert(std::is_permutation(ia, ia+sa, ia2));
  59
  60     test_with_iterator<random_access_iterator<int*> >();
  61     test_with_iterator<int*>();
  62
  63   return 0;
  64 }