libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count_if.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<InputIterator Iter, Predicate<auto, Iter::value_type> Pred>
  12 //   requires CopyConstructible<Pred>
  13 //   constexpr Iter::difference_type   // constexpr after C++17
  14 //   count_if(Iter first, Iter last, Pred pred);
  15
  16 #include <algorithm>
  17 #include <functional>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21 #include "test_iterators.h"
  22
  23 struct eq {
  24     TEST_CONSTEXPR eq (int val) : v(val) {}
  25     TEST_CONSTEXPR bool operator () (int v2) const { return v == v2; }
  26     int v;
  27     };
  28
  29 #if TEST_STD_VER > 17
  30 TEST_CONSTEXPR bool test_constexpr() {
  31     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
  32     int ib[] = {1, 2, 3, 4, 5, 6};
  33     return    (std::count_if(std::begin(ia), std::end(ia), eq(2)) == 3)
  34            && (std::count_if(std::begin(ib), std::end(ib), eq(9)) == 0)
  35            ;
  36     }
  37 #endif
  38
  39 int main(int, char**)
  40 {
  41     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
  42     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
  43     assert(std::count_if(input_iterator<const int*>(ia),
  44                          input_iterator<const int*>(ia + sa),
  45                          eq(2)) == 3);
  46     assert(std::count_if(input_iterator<const int*>(ia),
  47                          input_iterator<const int*>(ia + sa),
  48                          eq(7)) == 0);
  49     assert(std::count_if(input_iterator<const int*>(ia),
  50                          input_iterator<const int*>(ia),
  51                          eq(2)) == 0);
  52
  53 #if TEST_STD_VER > 17
  54     static_assert(test_constexpr());
  55 #endif
  56
  57   return 0;
  58 }