c++ - bool 变量可以存储超过 0x01 吗？

Question

#include <iostream>
#include <bitset>

using namespace std;

int main()
{
    bool a = 0x03;
    bitset<8> x(a);
    cout<<x<<endl;

    a = a>>1;
    bitset<8> y(a);
    cout<<y<<endl; 
}

结果是:

00000001    
00000000

结果不:

00000011
00000001

如果我将 a 的类型从 bool 更改为 char，结果将是第二个。这意味着我不能在 bool 中存储超过 0x01 的值，所有大于 0x01 的正确值都被视为 0x01。

所有编译器都有这个行为？

Answer 1

§4.12 boolean 转换 [conv.bool]

1 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer to member type can be converted to a prvalue of type bool. A zero value, null pointer value, or null member pointer value is converted to false; any other value is converted to true. A prvalue of type std::nullptr_t can be converted to a prvalue of type bool; the resulting value is false.