Question

我必须在这里做错事：我有这个枚举

enum OperetionFlags
{
        NONE = 0x01,
        TOUCHED = 0x02,
        MOVE_RIGHT = 0x04,
        MOVE_LEFT = 0x08,
        GAME_START = 0x10,
        GAME_END = 0x20
};

int curentState ;

没有我的程序启动，我设置：

main()
{
    curentState = 0 

    if (( curentState & GAME_START) == 0)
    {
        curentState |= GAME_START;
    }

    if ((curentState & MOVE_RIGHT) == 0)
    {
        curentState |= TOUCHED & MOVE_RIGHT;
    }

    if (curentState & GAME_START)
    {
        if (curentState & TOUCHED & MOVE_RIGHT) // HERE IS WHERE IT FAILED
        {

        }
    }

}

the curentState＆amp; TOUCHED＆amp; MOVE_RIGHT即使我设置了TOUCHED＆amp; MOVE_RIGHT位开启

Answer 1

使用按位运算，|类似于按位加法，&类似于按位乘法（如果有则丢弃进位）。
（很容易认为a & b是“a中的一位和b中的一位”，但它是“a和b中的一位”。）

让我们一起来：

curentState = 0 

    curentState is 00000000

if (( curentState & GAME_START) == 0)
{
    curentState |= GAME_START;
}

    curentState is now 00010000

if ((curentState & MOVE_RIGHT) == 0)
{
    curentState |= TOUCHED & MOVE_RIGHT;

        TOUCHED & MOVE_RIGHT is 00000000
        so curentState is still 00010000
}

if (curentState & GAME_START)
{
        curentState & TOUCHED is 00010000 & 00000010 = 00000000
        and 00000000 & MOVE_RIGHT is 00000000      

    if (curentState & TOUCHED & MOVE_RIGHT) // HERE IS WHERE IT FAILED
    {
    }
}

如果要设置这两个位，则需要使用|; TOUCHED | MOVE_RIGHT。

如果你想测试这两个位，你需要非常详细：

(curentState & (TOUCHED | MOVE_RIGHT)) == (TOUCHED | MOVE_RIGHT)

或使用逻辑and

单独测试它们

(curentState & TOUCHED) && (curentState & MOVE_RIGHT)

Answer 2

尝试

segmented

按位运算比较结果错误

2 个答案: