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 // <string> 10 11 // const_reference operator[](size_type pos) const; // constexpr since C++20 12 // reference operator[](size_type pos); // constexpr since C++20 13 14 #include <string> 15 #include <cassert> 16 17 #include "test_macros.h" 18 #include "min_allocator.h" 19 test()20TEST_CONSTEXPR_CXX20 bool test() { 21 { 22 typedef std::string S; 23 S s("0123456789"); 24 const S& cs = s; 25 ASSERT_SAME_TYPE(decltype( s[0]), typename S::reference); 26 ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference); 27 LIBCPP_ASSERT_NOEXCEPT( s[0]); 28 LIBCPP_ASSERT_NOEXCEPT( cs[0]); 29 for (S::size_type i = 0; i < cs.size(); ++i) 30 { 31 assert(s[i] == static_cast<char>('0' + i)); 32 assert(cs[i] == s[i]); 33 } 34 assert(cs[cs.size()] == '\0'); 35 const S s2 = S(); 36 assert(s2[0] == '\0'); 37 } 38 #if TEST_STD_VER >= 11 39 { 40 typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S; 41 S s("0123456789"); 42 const S& cs = s; 43 ASSERT_SAME_TYPE(decltype( s[0]), typename S::reference); 44 ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference); 45 LIBCPP_ASSERT_NOEXCEPT( s[0]); 46 LIBCPP_ASSERT_NOEXCEPT( cs[0]); 47 for (S::size_type i = 0; i < cs.size(); ++i) 48 { 49 assert(s[i] == static_cast<char>('0' + i)); 50 assert(cs[i] == s[i]); 51 } 52 assert(cs[cs.size()] == '\0'); 53 const S s2 = S(); 54 assert(s2[0] == '\0'); 55 } 56 #endif 57 58 return true; 59 } 60 main(int,char **)61int main(int, char**) 62 { 63 test(); 64 #if TEST_STD_VER > 17 65 static_assert(test()); 66 #endif 67 68 return 0; 69 } 70