如何將Enum型別的元素插入到uint8_t型別的向量中？-有解無憂

我對 C 編程很陌生。我想將列舉型別的元素插入到vector<uint8_t>? 即追加的所有元素。有沒有std::vector <ValType> call辦法 std::vector<uint8_t> bravo 這樣做？

#include <stdio.h>
#include <vector>
#include <cstdint>

enum class ValType : uint8_t
{

    Working = 1,
    Failed = 0,
    Freezed = 0

};

int main()
{
    std::vector<uint8_t> bravo = {23, 23, 23, 22, 5};
    std::vector<ValType> call;
    bravo.insert(bravo.end(), call.begin(), call.end());

    return 0;
}

住在這里

編譯時出現錯誤：

   In file included from c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\vector:66,
                 from custom.cpp:2:
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_uninitialized.h: In instantiation of '_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _ForwardIterator = unsigned char*]':
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_uninitialized.h:333:37:   required from '_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _ForwardIterator = unsigned char*; _Tp = unsigned char]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\vector.tcc:751:34:   required from 'void std::vector<_Tp, _Alloc>::_M_range_insert(std::vector<_Tp, _Alloc>::iterator, _ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_vector.h:1665:19:   required from 'void std::vector<_Tp, _Alloc>::_M_insert_dispatch(std::vector<_Tp, _Alloc>::iterator, _InputIterator, _InputIterator, std::__false_type) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_vector.h:1383:22:   required from 'std::vector<_Tp, _Alloc>::iterator std::vector<_Tp, _Alloc>::insert(std::vector<_Tp, _Alloc>::const_iterator, _InputIterator, _InputIterator) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; <template-parameter-2-2> = void; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator; std::vector<_Tp, _Alloc>::const_iterator = std::vector<unsigned char>::const_iterator]'  
custom.cpp:18:17:   required from here
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_uninitialized.h:138:72: error: static assertion failed: result type must be constructible from value type of input range
  138 |       static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
      |                                                                        ^~~~~
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_uninitialized.h:138:72: note: 'std::integral_constant<bool, false>::value' evaluates to false
In file included from c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\vector:60,
                 from custom.cpp:2:
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h: In instantiation of 'static _OI std::__copy_move<false, false, std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II = ValType*; _OI = unsigned char*]':
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h:495:30:   required from '_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false; _II = ValType*; _OI = unsigned char*]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h:522:42:   required from '_OI std::__copy_move_a1(_II, _II, _OI) [with bool _IsMove = false; _II = ValType*; _OI = unsigned char*]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h:530:31:   required from '_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false; _II = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _OI = __gnu_cxx::__normal_iterator<unsigned char*, std::vector<unsigned char> >]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h:620:7:   required from '_OI std::copy(_II, _II, _OI) [with _II = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _OI = __gnu_cxx::__normal_iterator<unsigned char*, std::vector<unsigned char> >]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\vector.tcc:744:16:   required from 'void std::vector<_Tp, _Alloc>::_M_range_insert(std::vector<_Tp, _Alloc>::iterator, _ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_vector.h:1665:19:   required from 'void std::vector<_Tp, _Alloc>::_M_insert_dispatch(std::vector<_Tp, _Alloc>::iterator, _InputIterator, _InputIterator, std::__false_type) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator]'
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_vector.h:1383:22:   required from 'std::vector<_Tp, _Alloc>::iterator std::vector<_Tp, _Alloc>::insert(std::vector<_Tp, _Alloc>::const_iterator, _InputIterator, _InputIterator) [with _InputIterator = __gnu_cxx::__normal_iterator<ValType*, std::vector<ValType> >; <template-parameter-2-2> = void; _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; std::vector<_Tp, _Alloc>::iterator = std::vector<unsigned char>::iterator; std::vector<_Tp, _Alloc>::const_iterator = std::vector<unsigned char>::const_iterator]'  
custom.cpp:18:17:   required from here
c:\program files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\include\c  \11.2.0\bits\stl_algobase.h:385:25: error: cannot convert 'ValType' to 'unsigned char' in assignment
  385 |               *__result = *__first;
      |               ~~~~~~~~~~^~~~~~~~~~

有人可以告訴我這樣做的正確方法嗎？

uj5u.com熱心網友回復：

您可以使用std::transform自己的轉換功能。

std::vector<uint8_t> bravo = {23, 23, 23, 22, 5};
std::vector<ValType> call;

std::transform(bravo.cbegin(), bravo.cend(), std::back_inserter(call),
               [](uint8_t a) { return static_cast<ValType>(a); });

uj5u.com熱心網友回復：

這在例如這個范圍列舉參考中有解釋：

沒有從作用域列舉器的值到整數型別的隱式轉換，盡管static_cast可以用于獲取列舉器的數值。

_{[強調我的]}

因此，雖然在定義列舉時它可能看起來像繼承，但事實并非如此。該型別ValType是一種完全獨立的型別，不能與任何其他普通整數型別相互轉換，甚至不能與用作列舉基型別的整數型別相互轉換。

這意味著您不能簡單地從一個元素向量復制到一個ValType元素向量uint8_t。如果你需要做這樣的復制，你必須實作你自己的轉換（使用 eg static_cast），也許使用std::transform和一個后插入迭代器。

轉載請註明出處，本文鏈接：https://www.uj5u.com/qukuanlian/537169.html

標籤：C C 11向量枚举C 17

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