59 lines · 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-exception6//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++1714// 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 23struct 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 > 1730TEST_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#endif38 39int 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(cpp17_input_iterator<const int*>(ia),44 cpp17_input_iterator<const int*>(ia + sa),45 eq(2)) == 3);46 assert(std::count_if(cpp17_input_iterator<const int*>(ia),47 cpp17_input_iterator<const int*>(ia + sa),48 eq(7)) == 0);49 assert(std::count_if(cpp17_input_iterator<const int*>(ia),50 cpp17_input_iterator<const int*>(ia),51 eq(2)) == 0);52 53#if TEST_STD_VER > 1754 static_assert(test_constexpr());55#endif56 57 return 0;58}59