test.pass.cpp (1687B)
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 // <iterator> 11 12 // reverse_iterator 13 14 // template <RandomAccessIterator Iter1, RandomAccessIterator Iter2> 15 // requires HasMinus<Iter2, Iter1> 16 // constexpr auto operator-(const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y) 17 // -> decltype(y.base() - x.base()); 18 // 19 // constexpr in C++17 20 21 #include <iterator> 22 #include <cstddef> 23 #include <cassert> 24 25 #include "test_macros.h" 26 #include "test_iterators.h" 27 28 template <class It1, class It2> 29 void 30 test(It1 l, It2 r, std::ptrdiff_t x) 31 { 32 const std::reverse_iterator<It1> r1(l); 33 const std::reverse_iterator<It2> r2(r); 34 assert((r1 - r2) == x); 35 } 36 37 int main() 38 { 39 char s[3] = {0}; 40 test(random_access_iterator<const char*>(s), random_access_iterator<char*>(s), 0); 41 test(random_access_iterator<char*>(s), random_access_iterator<const char*>(s+1), 1); 42 test(random_access_iterator<const char*>(s+1), random_access_iterator<char*>(s), -1); 43 test(s, s, 0); 44 test(s, s+1, 1); 45 test(s+1, s, -1); 46 47 #if TEST_STD_VER > 14 48 { 49 constexpr const char *p = "123456789"; 50 typedef std::reverse_iterator<const char *> RI; 51 constexpr RI it1 = std::make_reverse_iterator(p); 52 constexpr RI it2 = std::make_reverse_iterator(p+1); 53 static_assert( it1 - it2 == 1, ""); 54 static_assert( it2 - it1 == -1, ""); 55 } 56 #endif 57 }