libcxx/test/std/containers/sequences/array/indexing_const.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 // <array>
  10
  11 // const_reference operator[](size_type) const; // constexpr in C++14
  12 // Libc++ marks it as noexcept
  13
  14 #include <array>
  15 #include <cassert>
  16
  17 #include "test_macros.h"
  18
  19 // std::array is explicitly allowed to be initialized with A a = { init-list };.
  20 // Disable the missing braces warning for this reason.
  21 #include "disable_missing_braces_warning.h"
  22
  23
  24 TEST_CONSTEXPR_CXX14 bool tests()
  25 {
  26     {
  27         typedef double T;
  28         typedef std::array<T, 3> C;
  29         C const c = {1, 2, 3.5};
  30         LIBCPP_ASSERT_NOEXCEPT(c[0]);
  31         ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
  32         C::const_reference r1 = c[0];
  33         assert(r1 == 1);
  34         C::const_reference r2 = c[2];
  35         assert(r2 == 3.5);
  36     }
  37     // Test operator[] "works" on zero sized arrays
  38     {
  39         {
  40             typedef double T;
  41             typedef std::array<T, 0> C;
  42             C const c = {};
  43             LIBCPP_ASSERT_NOEXCEPT(c[0]);
  44             ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
  45             if (c.size() > (0)) { // always false
  46                 C::const_reference r = c[0];
  47                 (void)r;
  48             }
  49         }
  50         {
  51             typedef double T;
  52             typedef std::array<T const, 0> C;
  53             C const c = {};
  54             LIBCPP_ASSERT_NOEXCEPT(c[0]);
  55             ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
  56             if (c.size() > (0)) { // always false
  57               C::const_reference r = c[0];
  58               (void)r;
  59             }
  60         }
  61     }
  62
  63     return true;
  64 }
  65
  66 int main(int, char**)
  67 {
  68     tests();
  69 #if TEST_STD_VER >= 14
  70     static_assert(tests(), "");
  71 #endif
  72   return 0;
  73 }