比较（目标）C 中的枚举数组

发布于 2024-09-25 12:49:58 字数 585 浏览 2 评论 0原文

我想测试从一种状态到另一种状态的转换。我在这样的枚举中定义了我的状态：

enum FingerStatus {
FINGERS_UP,
MOVING,
FINGERS_STILL
};

我有一个“currentState”和一个“newState”变量。我知道枚举只是整数，如果它们是 16 位整数（我认为它们是），则可以将两个枚举表示为单个 32 位整数。

我觉得我应该能够按照

switch ({currentStatus, newFingerStatus}) {
    case {FINGERS_STILL, MOVING}:
        NSLog(@"fingers starting to move");
        break;
    case {MOVING, FINGERS_STILL}:
        NSLog(@"fingers stopped moving");
        break;
    default:
        break;
}

我意识到语法完全错误的方式做一些事情，但我认为基本想法是合理的。还有另一种好的、干净的方法来做到这一点吗？

原文

I want to test for transition from one state to another. I have defined my states in an enum like this:

enum FingerStatus {
FINGERS_UP,
MOVING,
FINGERS_STILL
};

I have a "currentState" and a "newState" variable. I know that enums are just integers, and if they're 16-bit integers, which I think they are, it's possible to represent two enums as a single 32-bit integer.

I feel like I ought to be able to do something along the lines of

switch ({currentStatus, newFingerStatus}) {
    case {FINGERS_STILL, MOVING}:
        NSLog(@"fingers starting to move");
        break;
    case {MOVING, FINGERS_STILL}:
        NSLog(@"fingers stopped moving");
        break;
    default:
        break;
}

I realize the syntax is all wrong, but I think the basic idea is sound. Is there another nice, clean way to do this?

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二智少女 2024-10-02 12:49:58

如果你能保证你的枚举小于 16 位，那么这将起作用：

switch ((currentStatus<<16) + newFingerStatus) {
    case (FINGERS_STILL<<16) + MOVING:
        NSLog(@"fingers starting to move");
        break;
    case (MOVING<<16) + FINGERS_STILL:
        NSLog(@"fingers stopped moving");
        break;
    default:
        break;
}

If you can guarantee your enums are less than 16 bits, this will work:

switch ((currentStatus<<16) + newFingerStatus) {
    case (FINGERS_STILL<<16) + MOVING:
        NSLog(@"fingers starting to move");
        break;
    case (MOVING<<16) + FINGERS_STILL:
        NSLog(@"fingers stopped moving");
        break;
    default:
        break;
}

回复收藏 0 原文

与他有关 2024-10-02 12:49:58

由于开关只是一种编写 goto 的奇特方式，因此您不能使用它们来做您想做的事情。使用 if 代替：

if(currentStatus == FINGERS_STILL && newFingerStatus == MOVING)
{
    NSLog(@"fingers starting to move");
}
else if(currentStatus == MOVING && newFingerStatus == FINGERS_STILL)
{
    NSLog(@"fingers stopped moving");
}

Since switches are just a fancy way to write gotos, you can't use them to do what you want to do. Use ifs instead:

if(currentStatus == FINGERS_STILL && newFingerStatus == MOVING)
{
    NSLog(@"fingers starting to move");
}
else if(currentStatus == MOVING && newFingerStatus == FINGERS_STILL)
{
    NSLog(@"fingers stopped moving");
}

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や莫失莫忘 2024-10-02 12:49:58

整数可以超过16位，在计算机上通常是32位（不确定iPhone），但你的想法仍然有效。

您可以使用 (intOne + ( intTwo << 4 )) 将两个 int 放在一起，进行比较和评估。

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娇俏 2024-10-02 12:49:58

对于一个人来说，给枚举不同的唯一值可能是明智的：1,2,4而不是0,1,2，然后你可以按位或它们。然后你可以做这样的标签：

case FINGERS_STILL|MOVING:

well for one it would probably wise to give the enums different unique values: 1,2,4 and not 0,1,2 then you can bitwise or them. Then you can do labels like: