libstdc++-v3/testsuite/25_algorithms/generate_n/constrained.cc

   1 // Copyright (C) 2020-2025 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run { target c++20 } }
  19
  20 #include <algorithm>
  21 #include <testsuite_hooks.h>
  22 #include <testsuite_iterators.h>
  23
  24 using __gnu_test::test_container;
  25 using __gnu_test::test_range;
  26 using __gnu_test::input_iterator_wrapper;
  27 using __gnu_test::output_iterator_wrapper;
  28 using __gnu_test::forward_iterator_wrapper;
  29
  30 namespace ranges = std::ranges;
  31
  32 void
  33 test01()
  34 {
  35   const int c[6] = { 1, 2, 3, 4, 5, 6 };
  36
  37     {
  38       int x[6] = { 7, 8, 9, 4, 5, 6 };
  39       int a = 1;
  40       VERIFY( ranges::generate_n(x, 3, [&] { return a++; }) == x+3 );
  41       VERIFY( ranges::equal(x, c) );
  42     }
  43
  44     {
  45       int x[6] = { 7, 8, 9, 4, 5, 6 };
  46       int a = 1;
  47       test_container<int, forward_iterator_wrapper> cx(x);
  48       VERIFY( *ranges::generate_n(cx.begin(), 3, [&] { return a++; })
  49                == 4 );
  50       VERIFY( ranges::equal(cx, c) );
  51     }
  52
  53     {
  54       int x[6] = { 7, 8, 9, 4, 5, 6 };
  55       int a = 1;
  56       test_range<int, output_iterator_wrapper> rx(x);
  57       ranges::generate_n(ranges::begin(rx), 3, [&] { return a++; });
  58       VERIFY( ranges::equal(x, c) );
  59     }
  60 }
  61
  62 constexpr bool
  63 test02()
  64 {
  65   bool ok = true;
  66   int c[6] = { 1, 2, 3, 4, 5, 6 };
  67   int x[6];
  68   int a = 1;
  69   ranges::generate_n(x, 6, [&] { return a++; });
  70   ok &= ranges::equal(x, c);
  71   ranges::generate_n(c, 0, [] { return -1; });
  72   ok &= ranges::equal(x, c);
  73   ranges::generate_n(c, -2, [] { return -1; });
  74   ok &= ranges::equal(x, c);
  75   return ok;
  76 }
  77
  78 int
  79 main()
  80 {
  81   test01();
  82   static_assert(test02());
  83 }