C++程序  |  49行  |  1.54 KB

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <utility>

// template<class T, T... I>
// struct integer_sequence
// {
//     typedef T type;
// 
//     static constexpr size_t size() noexcept;
// };

#include <utility>
#include <type_traits>
#include <cassert>

int main()
{
#if _LIBCPP_STD_VER > 11

//  Make a few of sequences
    using int3    = std::integer_sequence<int, 3, 2, 1>;
    using size1   = std::integer_sequence<size_t, 7>;
    using ushort2 = std::integer_sequence<unsigned short, 4, 6>;
    using bool0   = std::integer_sequence<bool>;
    
//  Make sure they're what we expect
    static_assert ( std::is_same<int3::value_type, int>::value, "int3 type wrong" );
    static_assert ( int3::size() == 3, "int3 size wrong" );
    
    static_assert ( std::is_same<size1::value_type, size_t>::value, "size1 type wrong" );
    static_assert ( size1::size() == 1, "size1 size wrong" );
    
    static_assert ( std::is_same<ushort2::value_type, unsigned short>::value, "ushort2 type wrong" );
    static_assert ( ushort2::size() == 2, "ushort2 size wrong" );
    
    static_assert ( std::is_same<bool0::value_type, bool>::value, "bool0 type wrong" );
    static_assert ( bool0::size() == 0, "bool0 size wrong" );
    
#endif  // _LIBCPP_STD_VER > 11
}