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() 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