如何反转find_if？ [英] how to reverse find_if?
问题描述
以下find_if对我来说很好，除了我想要向后执行内部
个别比较（从m + 5，m + 4，...，到m）。我可以使用reverse（）来反转数组，但这会引入
开销（整个数组的副本）。似乎我可以使用反向的
迭代器但是数组m不是标准的STL容器，例如
向量。可能吗？非常感谢你的帮助。
float m [6];
float * p = find_if（m，m + 6，bind2nd（greater_equal< float> （），14.5））;
Tony
JDT写道：
以下find_if对我来说很好，除了我想要向后执行内部
个别比较（从m + 5，m + 4，...到m）。我可以使用reverse（）来反转数组，但这会引入
开销（整个数组的副本）。似乎我可以使用反向的
迭代器但是数组m不是标准的STL容器，例如
向量。可能吗？非常感谢你的帮助。
float m [6];
float * p = find_if（m，m + 6，bind2nd（greater_equal< float> （），14.5））;
我认为你可以使用带指针的std :: reverse_iterator。见24.1.1
即：
typedef std :: reverse_iterator< float * rfloat_iter;
rfloat_iter p =
std :: find_if（rfloat_iter（m + 6），rfloat_iter（m），
std :: bind2nd（greater_equal< float>（），14.5））;
嗨红，
感谢您的帮助。首先，24.1.1是什么意思？
其次，我正在测试你的代码。要检查find_if是否找到了某些内容，
我应该使用p == rfloat_iter（m + 6）或p == rfloat_iter（m）？此外，
是m + 5和m-1之间的范围？
您的代码有一些编译错误。我很感激，如果有人能告诉我
什么是正确的语法（因为我对这方面不熟悉）。
感谢您提供进一步的帮助。
Tony
red floyd写道：
JDT写道：
< blockquote class =post_quotes>
>
以下find_if对我来说很好，除了我想要向后执行内部
个人比较（从m + 5， m + 4，...，到m）。
我可以先使用reverse（）来反转数组，但这会引入开销（整个数组的副本）。似乎我可以使用
反向迭代器但是数组m不是标准的STL容器，例如矢量。可能吗？非常感谢你的帮助。
float m [6];
float * p = find_if（m，m + 6，bind2nd（greater_equal< float>（），14.5））;
我认为你可以使用带指针的std :: reverse_iterator。见24.1.1
即：
typedef std :: reverse_iterator< float * rfloat_iter;
rfloat_iter p =
std :: find_if（rfloat_iter（m + 6），rfloat_iter（m），
std :: bind2nd（greater_equal< float>（），14.5））;
JDT写道：
red floyd写道：
>我认为你可以使用带指针的std :: reverse_iterator。见24.1.1
typedef std :: reverse_iterator< float * rfloat_iter;
rfloat_iter p =
std :: find_if（rfloat_iter（m + 6），rfloat_iter（m），
std :: bind2nd（greater_equal< float>（），14.5））;
感谢您的帮助。首先，你对24.1.1的意思是什么？
ISO C ++标准（ISO / IEC 14882：2003）第24.1.1节。
我正在测试你的代码。要检查find_if是否找到了某些内容，我是否应该使用p == rfloat_iter（m + 6）"或p == rfloat_iter（m）？
后者。
此外，m + 5和m-1之间的范围是多少？
排序。有关详细信息，请参见24.1.1。
您的代码存在一些编译错误。我很感激，如果有人能告诉我
什么是正确的语法（因为我不熟悉这方面）。
我并不感到惊讶，我把它写在了我的头顶。我敢肯定，这里其他更知识渊博的人可以帮助你比我更多。
另外，作为礼仪问题，请尽量不要发帖（在你回复的内容之上张贴所有文件） - 在这个
新闻组中，它不赞成。相反，将你的回复与你提到的文本（正如我在这里所做的那样）或文本之后一起散布。
Hi,
The following find_if works fine to me except that I want the internal
individual comparison performed backward (from m+5, m+4, ..., to m). I
can use reverse() to reverse the array first but that introduces
overhead (a copy of the whole array). It seems that I can use a reverse
iterator but the array m is not a standard STL container such as a
vector. Is it possible? Your help is much appreciated.
float m[6];
float *p = find_if(m, m+6, bind2nd(greater_equal<float>(), 14.5));
Tony
JDT wrote:Hi,
The following find_if works fine to me except that I want the internal
individual comparison performed backward (from m+5, m+4, ..., to m). I
can use reverse() to reverse the array first but that introduces
overhead (a copy of the whole array). It seems that I can use a reverse
iterator but the array m is not a standard STL container such as a
vector. Is it possible? Your help is much appreciated.
float m[6];
float *p = find_if(m, m+6, bind2nd(greater_equal<float>(), 14.5));
I think that you can use std::reverse_iterator with a pointer. See 24.1.1
i.e.:
typedef std::reverse_iterator<float *rfloat_iter;
rfloat_iter p =
std::find_if(rfloat_iter(m+6), rfloat_iter(m),
std::bind2nd(greater_equal<float>(), 14.5));
Hi Red,
Thanks for your help. First of all, what do you mean by 24.1.1?
Second, I am testing your code. To check if find_if finds something,
should I use "p == rfloat_iter(m+6)" or "p == rfloat_iter(m)"? Besides,
is the range between m+5 and m-1?
Your code has some compile errors. I appreciate if somebody can show me
what''s the correct syntax (because I am not familiar with this regard).
Thanks for any further help.
Tony
red floyd wrote:
JDT wrote:
>Hi,
The following find_if works fine to me except that I want the internal
individual comparison performed backward (from m+5, m+4, ..., to m).
I can use reverse() to reverse the array first but that introduces
overhead (a copy of the whole array). It seems that I can use a
reverse iterator but the array m is not a standard STL container such
as a vector. Is it possible? Your help is much appreciated.
float m[6];
float *p = find_if(m, m+6, bind2nd(greater_equal<float>(), 14.5));
I think that you can use std::reverse_iterator with a pointer. See 24.1.1
i.e.:
typedef std::reverse_iterator<float *rfloat_iter;
rfloat_iter p =
std::find_if(rfloat_iter(m+6), rfloat_iter(m),
std::bind2nd(greater_equal<float>(), 14.5));
JDT wrote:
red floyd wrote:>I think that you can use std::reverse_iterator with a pointer. See 24.1.1
typedef std::reverse_iterator<float *rfloat_iter;
rfloat_iter p =
std::find_if(rfloat_iter(m+6), rfloat_iter(m),
std::bind2nd(greater_equal<float>(), 14.5));
Thanks for your help. First of all, what do you mean by 24.1.1?Section 24.1.1 of the ISO C++ Standard (ISO/IEC 14882:2003).
I am testing your code. To check if find_if finds something, should I
use "p == rfloat_iter(m+6)" or "p == rfloat_iter(m)"?The latter.
Besides, is the range between m+5 and m-1?Sort of. See 24.1.1 for more details.
Your code has some compile errors. I appreciate if somebody can show me
what''s the correct syntax (because I am not familiar with this regard).I''m not surprised, I wrote it off the top of my head. I''m sure that one
of the other more knowledgeable types here can help you more than me.
Also, as a matter of etiquette, please try not to top-post (posting all
your text above what you''re replying to) -- it''s frowned on in this
newsgroup. Instead, intersperse your replies with the text you''re
referring to (as I did here), or after the text.
这篇关于如何反转find_if？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
