libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.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 // UNSUPPORTED: c++03
  10
  11 // <utility>
  12
  13 // template <class T1, class T2> struct pair
  14
  15 // struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
  16 // constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
  17
  18 #include <utility>
  19 #include <tuple>
  20 #include <cassert>
  21
  22 #include "test_macros.h"
  23
  24 class A
  25 {
  26     int i_;
  27     char c_;
  28 public:
  29     constexpr A(int i, char c) : i_(i), c_(c) {}
  30     constexpr int get_i() const {return i_;}
  31     constexpr char get_c() const {return c_;}
  32 };
  33
  34 class B
  35 {
  36     double d_;
  37     unsigned u1_;
  38     unsigned u2_;
  39 public:
  40     constexpr explicit B(double d, unsigned u1, unsigned u2) : d_(d), u1_(u1), u2_(u2) {}
  41     constexpr double get_d() const {return d_;}
  42     constexpr unsigned get_u1() const {return u1_;}
  43     constexpr unsigned get_u2() const {return u2_;}
  44 };
  45
  46 TEST_CONSTEXPR_CXX20
  47 bool test()
  48 {
  49     std::pair<A, B> p(std::piecewise_construct,
  50                       std::make_tuple(4, 'a'),
  51                       std::make_tuple(3.5, 6u, 2u));
  52     assert(p.first.get_i() == 4);
  53     assert(p.first.get_c() == 'a');
  54     assert(p.second.get_d() == 3.5);
  55     assert(p.second.get_u1() == 6u);
  56     assert(p.second.get_u2() == 2u);
  57
  58     return true;
  59 }
  60
  61 int main(int, char**)
  62 {
  63     test();
  64 #if TEST_STD_VER >= 20
  65     static_assert(test());
  66 #endif
  67
  68     return 0;
  69 }