reduce_init_op.pass.cpp (2360B)
1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <numeric> 11 // UNSUPPORTED: c++98, c++03, c++11, c++14 12 13 // template<class InputIterator, class T, class BinaryOperation> 14 // T reduce(InputIterator first, InputIterator last, T init, BinaryOperation op); 15 16 #include <numeric> 17 #include <cassert> 18 19 #include "test_iterators.h" 20 21 template <class Iter, class T, class Op> 22 void 23 test(Iter first, Iter last, T init, Op op, T x) 24 { 25 static_assert( std::is_same_v<T, decltype(std::reduce(first, last, init, op))>, "" ); 26 assert(std::reduce(first, last, init, op) == x); 27 } 28 29 template <class Iter> 30 void 31 test() 32 { 33 int ia[] = {1, 2, 3, 4, 5, 6}; 34 unsigned sa = sizeof(ia) / sizeof(ia[0]); 35 test(Iter(ia), Iter(ia), 0, std::plus<>(), 0); 36 test(Iter(ia), Iter(ia), 1, std::multiplies<>(), 1); 37 test(Iter(ia), Iter(ia+1), 0, std::plus<>(), 1); 38 test(Iter(ia), Iter(ia+1), 2, std::multiplies<>(), 2); 39 test(Iter(ia), Iter(ia+2), 0, std::plus<>(), 3); 40 test(Iter(ia), Iter(ia+2), 3, std::multiplies<>(), 6); 41 test(Iter(ia), Iter(ia+sa), 0, std::plus<>(), 21); 42 test(Iter(ia), Iter(ia+sa), 4, std::multiplies<>(), 2880); 43 } 44 45 template <typename T, typename Init> 46 void test_return_type() 47 { 48 T *p = nullptr; 49 static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}, std::plus<>()))>, "" ); 50 } 51 52 int main() 53 { 54 test_return_type<char, int>(); 55 test_return_type<int, int>(); 56 test_return_type<int, unsigned long>(); 57 test_return_type<float, int>(); 58 test_return_type<short, float>(); 59 test_return_type<double, char>(); 60 test_return_type<char, double>(); 61 62 test<input_iterator<const int*> >(); 63 test<forward_iterator<const int*> >(); 64 test<bidirectional_iterator<const int*> >(); 65 test<random_access_iterator<const int*> >(); 66 test<const int*>(); 67 68 // Make sure the math is done using the correct type 69 { 70 auto v = {1, 2, 3, 4, 5, 6, 7, 8}; 71 unsigned res = std::reduce(v.begin(), v.end(), 1U, std::multiplies<>()); 72 assert(res == 40320); // 8! will not fit into a char 73 } 74 }