在C中需要一个队列 [英] Need a queue in C
问题描述
我需要一个大小为20的FIFO队列，以跟踪一个运行平均值。
一旦队列满了20个值，我想取总和/ 20 =
AVERAGE。然后当一个新值出现时，我想要：
（旧和 - 最旧值+最新值）/ 20 =新平均值
有人知道一种有效的方法吗？队列甚至是最好的方式吗？
谢谢，
I need a FIFO queue of size 20, to keep track of a running average.
Once the queue is full with 20 values, I want to take the sum/20 =
AVERAGE. Then when a new value comes in, I want:
(Old Sum - oldest value + newest value)/20 = New Average
Anybody know an efficient way to implement that? Is a queue even the
best way?
Thanks,
推荐答案
ern写道：
我需要一个大小为20的FIFO队列来跟踪一个运行平均值。
一旦队列满了20个值，我想拿总和/ 20 =
AVERAGE。然后当一个新值出现时，我想要：
（旧和 - 最旧的值+最新值）/ 20 =新的平均值
任何人都知道一种有效的方法来实现它？排队甚至是最好的方式吗？
I need a FIFO queue of size 20, to keep track of a running average.
Once the queue is full with 20 values, I want to take the sum/20 =
AVERAGE. Then when a new value comes in, I want:
(Old Sum - oldest value + newest value)/20 = New Average
Anybody know an efficient way to implement that? Is a queue even the
best way?
这看起来不像C问题，因为问题会是
$ b对于任何编程语言，$ b都是相同的。这听起来更像是数据结构和算法问题。或者也许是家庭作业
问题。
话虽如此，除非你有一个
$ b，否则我不会使用队列$ b队列实现已经完成，你可以使用。原因是，
因为它具有在编译时已知的固定大小，所以你不需要处理具有可以具有的数据结构的复杂性。
中可变数值。
因此，我会使用一个非常简单的数据结构，我会有
a语句在我的程序中看起来像这样：
index =（index + 1）％20;
- Logan
This doesn''t really seem like a C question, since the question would
be the same for just about any programming language. It sounds more
like a data structures and algorithms question. Or maybe a homework
question.
Having said that, I wouldn''t use a queue for this unless you have a
queue implementation already done that you can use. The reason is,
since it has a fixed size known at compile time, you don''t need to
handle the complexity of having a data structure that can have a
variable number of values in it.
Therefore, I would use a very simple data structure and I would have
a statement in my program that looks like this:
index = (index + 1) % 20;
- Logan
Logan Shaw写道：
Logan Shaw wrote:
这看起来不像C问题，因为问题会<几乎任何编程语言都是一样的。听起来更像数据结构和算法问题。或者也许是家庭作业
的问题。
uhhh ...这是一个C问题，因为C不支持std :: queue。
这不是一个功课问题......它实际上更像是一个嵌入式的
系统问题，因为我正在采用浮点电流的值
（模拟 - >数字） 。这些值是波动的，所以我需要实现一些东西来稳定输出。现在，我正在使用
qsort并取中位数。这工作得很好，但是我的应用程序很多都在减慢
。
因为它在编译时已知固定大小，你不需要处理具有可变数值的数据结构的复杂性。
难道你不是要创建一个没有变量
大小的数据结构来避免这种情况吗？
因此，我会使用一个非常简单的数据结构，我会在我的程序中有一个如下所示的语句：
这个数据结构会是什么样的？
说非常简单的数据结构并没有真正帮助。
index =（index + 1）％20;
This doesn''t really seem like a C question, since the question would
be the same for just about any programming language. It sounds more
like a data structures and algorithms question. Or maybe a homework
question.
uhhh... it kind of IS a C question since C doesn''t support std::queue.
It''s not a homework question... it''s actually more of an embedded
systems question, since I''m taking values of floating point current
(analog -> digital). The values are fluctuating, so I need to
implement something to stabilize the output. Right now, I''m using
qsort and taking the median. This is working great, but it''s slowing
down my application a lot.
since it has a fixed size known at compile time, you don''t need to
handle the complexity of having a data structure that can have a
variable number of values in it.
Wouldn''t you just create a data structure that doesn''t have variable
size to avoid this?
Therefore, I would use a very simple data structure and I would have
a statement in my program that looks like this:
What would that data structure look like? It doesn''t really help to
say "very simple data structure."
index = (index + 1) % 20;
是的...我知道的很多......
yeah... i know that much...
2006-01-13，Logan Shaw< ; LS ********** @ austin.rr.com>写道：
On 2006-01-13, Logan Shaw <ls**********@austin.rr.com> wrote:
ern写道：
我需要一个大小为20的FIFO队列来跟踪一个运行平均值。
一旦队列满了20个值，我想取总和/ 20 =
AVERAGE。然后当一个新值进来时，我想：
I need a FIFO queue of size 20, to keep track of a running average.
Once the queue is full with 20 values, I want to take the sum/20 =
AVERAGE. Then when a new value comes in, I want:
因此，我会使用一个非常简单的数据结构，我会在我的程序中有一个如下所示的语句：
index =（index + 1）％20;
Therefore, I would use a very simple data structure and I would have
a statement in my program that looks like this:
index = (index + 1) % 20;
这看起来类似于循环数组队列。
队列没有必须使用动态分配来实现
是吗？
然后再说一次，也许这是一项任务，而且需要动态分配
。 :-)
-
Ioan - Ciprian Tandau
tandau _at_ freeshell _dot_ org（希望它不是太多晚了）
（......它仍然可以......）
This looks similar to a circular array queue.
A queue doesn''t have to be implemented using dynamic allocation
does it?
Then again, maybe this is an assignment and ern needs dynamic
allocation. :-)
--
Ioan - Ciprian Tandau
tandau _at_ freeshell _dot_ org (hope it''s not too late)
(... and that it still works...)
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