C ++中不是只枚举整数吗？

Question

我一直认为在 C ++ 和 C 中，enum都是整数。但是今天我得到了“从int到E的无效转换”：

enum E {
    FIRST = 0b01,
    SECOND = 0b10,
    THIRD = FIRST | SECOND  // this is fine
};

int main()
{
    E first = FIRST;
    E third = FIRST | SECOND; // this is NOT fine

    return 0;
}

Answer 1

您应该强制转换它，因为它的类型为int，这样就可以实现您的目标

E first = FIRST;
E third = static_cast<E>(FIRST | SECOND);