在构造函数中分配Array时出错

Question

这是我面临的一个奇怪的问题 - 考虑到我生锈的C++技能,可能是超基本的东西,但我仍然感到困惑:

• 我上了课
• 我们unsigned long long在这堂课中也有一系列的- 让我们称之为arr

我的班级界面:

typedef unsigned long long U64;

class DQClass
{
    public:
        DQClass (void);
        virtual ~DQClass (void);

        U64 arr[12];
};

现在至于实施......

测试1(这是有效的):

DQClass::DQClass (void)
{
        this->arr[0] = 0x8100000000000000ULL;
        this->arr[1] = 0x4200000000000000ULL;

        // and so on..
}

测试2(这不):

DQClass::DQClass (void)
{
    this->arr = 
    {
        0x8100000000000000ULL,
        0x4200000000000000ULL,
        0x2400000000000000ULL,
        0x1000000000000000ULL,
        0x0800000000000000ULL,
        0x00FF000000000000ULL,
        FLIPV(0x8100000000000000ULL),
        FLIPV(0x4200000000000000ULL),
        FLIPV(0x2400000000000000ULL),
        FLIPV(0x1000000000000000ULL),
        FLIPV(0x0800000000000000ULL),
        FLIPV(0x00FF000000000000ULL)
    };
}

错误:

dqclass.cpp: In constructor ‘DQClass::DQClass()’:
dqclass.cpp:28: error: expected primary-expression before ‘{’ token
dqclass.cpp:28: error: expected `;' before ‘{’ token

---

为什么这不起作用？它不应该以同样的方式工作,例如U64 someArr[12] = {0,1,2,3,4,5,6,7,8,9,10,11}吗？

有任何想法吗？

Answer 1

数组不能像那样(或任何其他方式)分配,只能初始化:

 // sorry for bad formatting
DQClass::DQClass (void)
: arr(
    {
        0x8100000000000000ULL,
        0x4200000000000000ULL,
        0x2400000000000000ULL,
        0x1000000000000000ULL,
        0x0800000000000000ULL,
        0x00FF000000000000ULL,
        FLIPV(0x8100000000000000ULL),
        FLIPV(0x4200000000000000ULL),
        FLIPV(0x2400000000000000ULL),
        FLIPV(0x1000000000000000ULL),
        FLIPV(0x0800000000000000ULL),
        FLIPV(0x00FF000000000000ULL)
    }) {
}

使用构造函数初始化列表.

你也可以使用std::array:

std::array<U64, 12> arr;

// ...

this->arr = 
    {{
        0x8100000000000000ULL,
        0x4200000000000000ULL,
        0x2400000000000000ULL,
        0x1000000000000000ULL,
        0x0800000000000000ULL,
        0x00FF000000000000ULL,
        FLIPV(0x8100000000000000ULL),
        FLIPV(0x4200000000000000ULL),
        FLIPV(0x2400000000000000ULL),
        FLIPV(0x1000000000000000ULL),
        FLIPV(0x0800000000000000ULL),
        FLIPV(0x00FF000000000000ULL)
    }};