Question

我目前正在尝试声明一个由 17 个 std::bitset 组成的数组，每个 32 位长。我是这样做的：

std::bitset<32> mTestInstruction[17]
{
    std::string("01000000001000000000000000000001"),
    std::string("01000000011000000000000001100011"),
    std::string("01000000101000000000000000000001"),
    std::string("10100000000000000000000000001010"),
    std::string("00000000100000010000000010000010"),
    std::string("00000000110001010010000000000001"),
    std::string("01001000111001010000000000000000"),
    std::string("01000100001000110000000000000011"),
    std::string("01000000001000010000000000000001"),
    std::string("10000000000000000000000000000011"),
    std::string("00000000010000000000000000000001"),
    std::string("00000000111000000000000000000001"),
    std::string("00000000111001110000100000000001"),
    std::string("01000000010000100000000000000001"),
    std::string("01000100001000100000000000000010"),
    std::string("10000000000000000000000000001100"),
    std::string("11100000000000000000000000001000"),
};

我收到以下错误：

<块引用>

error: could not convert 'std::__cxx11::basic_string<char>(((const char*)"01000000001000000000000000000001"), std::allocator<char>())' from 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}' to 'std::bitset<32u>'

对于每个位串。

我不明白为什么会发生这种情况，因为根据 cpp 参考，std::string 是构造位集的有效方法。谁能指出如何解决这个问题？

Answer 1

您需要像这样调用 std::bitset 的构造函数：

std::bitset< 32 > mTestInstruction[17]
{
    std::bitset< 32 >( std::string( "01000000001000000000000000000001" ) ),
    std::bitset< 32 >( std::string( "01000000011000000000000001100011" ) ),
    // ...
};

甚至更短：

std::bitset< 32 > mTestInstruction[17]
{
    std::bitset< 32 >( "01000000001000000000000000000001" ),
    std::bitset< 32 >( "01000000011000000000000001100011" ),
    // ...
};

您的代码不起作用的原因是 std::bitset 接受 std::string 的构造函数被标记为显式（请参阅 here）。

从 C++14 开始，您可以使用二进制文字，例如：

std::bitset< 32 > mTestInstruction[17]
{
    0b01000000001000000000000000000001,
    0b01000000011000000000000001100011,
    // ...
};

Answer 2

你可以这样做：

std::bitset<32> mTestInstruction[17]{
        std::bitset<32>{std::string("01000000001000000000000000000001")},
        std::bitset<32>{std::string("01000000011000000000000001100011")},
        std::bitset<32>{std::string("01000000101000000000000000000001")},
        std::bitset<32>{std::string("10100000000000000000000000001010")},
        std::bitset<32>{std::string("00000000100000010000000010000010")},
        std::bitset<32>{std::string("00000000110001010010000000000001")},
        std::bitset<32>{std::string("01001000111001010000000000000000")},
        std::bitset<32>{std::string("01000100001000110000000000000011")},
        std::bitset<32>{std::string("01000000001000010000000000000001")},
        std::bitset<32>{std::string("10000000000000000000000000000011")},
        std::bitset<32>{std::string("00000000010000000000000000000001")},
        std::bitset<32>{std::string("00000000111000000000000000000001")},
        std::bitset<32>{std::string("00000000111001110000100000000001")},
        std::bitset<32>{std::string("01000000010000100000000000000001")},
        std::bitset<32>{std::string("01000100001000100000000000000010")},
        std::bitset<32>{std::string("10000000000000000000000000001100")},
        std::bitset<32>{std::string("11100000000000000000000000001000")},
    };

使用 std::string

2 个答案: