ATL / WTL / STL

Re: C++ MFC - DatePickerControl - DTN_DATETIMECHANGE event getting triggered twice when clicked !!!!

12-Aug-10 4:17

Can I suggest you post this question to the correct forum, rather than this one, which doesn't cover MFC...

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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Kausik4u12-Aug-10 4:27

Kausik4u

12-Aug-10 4:27

Thanks Stuart. I moved it to C / C++ / MFC. Hope that will help.

Tranlating old code to the STL style

VeganFanatic8-Aug-10 4:47

8-Aug-10 4:47

OK I found a sort algorithm on Wikipedia, that is done like the std::sort so I figured why not convert the who lot that I have to STL. Blah.

First the new sort

template<class ForwardIterator> void comb(ForwardIterator first, ForwardIterator last){
    static const double shrink_factor = 1.247330950103979;
    typedef typename std::iterator_traits<ForwardIterator>::difference_type difference_type;
    difference_type gap = std::distance(first, last);
    bool swaps = true;
    while ( (gap > 1) || (swaps == true) ){
        if (gap > 1)
            gap = static_cast<difference_type>(gap/shrink_factor);
        swaps = false;
        ForwardIterator itLeft(first);
        ForwardIterator itRight(first); std::advance(itRight, gap);
        for ( ; itRight!=last; ++itLeft, ++itRight ){
            if ( (*itRight) < (*itLeft) ){
                std::iter_swap(itLeft, itRight);
                swaps = true;
            }
        }
    }
}

So now the old bubble sort

template <typename T> void bubble(std::vector<T> &a) { // O(n^2)
	size_t size = a.size() - 1;
    for (int pass = 0; pass < size; pass++) {
		for (int n = 0; n < size; n++) {
			if (a[n] > a[n+1])
				std::swap(a[n], a[n+1]);
        }
    }
}

and this is as far as I have gone so far

template<class ForwardIterator> void bubble(ForwardIterator first, ForwardIterator last){
    typedef typename std::iterator_traits<ForwardIterator>::difference_type difference_type;
    difference_type size = std::distance(first, last);
}

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Stuart Dootson12-Aug-10 4:13

12-Aug-10 4:13

How's this?

template <typename T>
void bubble(std::vector<T> &a)
{
   typedef typename std::vector<T>::iterator Iter;
   Iter last = a.end()-1;
   for(Iter pass=a.begin();pass!=last;++pass)
      for(Iter n=a.begin();n!=last;++n)
         if (*n > *(n+1))
            std::iter_swap(n, n+1);
}

or this, which doesn't keep re-sorting the items at the end of the vector that have already been sorted…

template <typename T>
void bubble(std::vector<T> &a)
{
   typedef typename std::vector<T>::iterator Iter;
   for(Iter last = a.end()-1;last!=a.begin();--last)
      for(Iter n=a.begin();n!=last;++n)
         if (*n > *(n+1))
            std::iter_swap(n, n+1);
}

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

CodeProject MVP for 2010 - who'd'a thunk it!

VeganFanatic12-Aug-10 8:33

12-Aug-10 8:33

After a few moments looking over the book I figured out that I need to watch the pointers close when using the STL method of iterators.

This is not well covered in any of the books I have. No big deal, that is what forums are for.

Here is what I ended up with that does work properly.

template <typename iterator> void bubble(iterator first, iterator last) { // O(n^2)
     iterator i, j;
     for (i = first; i != last; ++i)
         for (j = first; j < i; ++j)
             if (*i < *j)
                 std::iter_swap(i, j); // or std::swap(*i, *j);
}

Now I have this other sort that is annoying me.

template <class iterator> void gnome(iterator first, iterator last){ // O(n^2)
	iterator pos = first;
	iterator temp;
	while (pos <= last) {
		if ((pos == first) || (*pos >= *(pos-1)))
			++pos;
		else {
			//{int tmp = ar[i]; ar[i] = ar[i-1]; ar[--i] = tmp;}
			std::iter_swap(pos, pos-1);
			--pos;
		}
	}
}

This one does not work, not sure what the problem is.

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Stuart Dootson12-Aug-10 8:51

12-Aug-10 8:51

What iterators are you calling it with?

This sample program seems to sort the data OK…

#include <vector>
#include <iostream>
#include <iterator>

template <class iterator> void gnome(iterator first, iterator last){ // O(n^2)
  iterator pos = first;
  iterator temp;
  while (pos <= last) {
    if ((pos == first) || (*pos >= *(pos-1)))
      ++pos;
    else {
      //{int tmp = ar[i]; ar[i] = ar[i-1]; ar[--i] = tmp;}
      std::iter_swap(pos, pos-1);
      --pos;
    }
  }
}

int main(int, char**)
{
  std::vector<int> vec;
  
  vec.push_back(4);
  vec.push_back(3);
  vec.push_back(5);
  vec.push_back(-10);
  vec.push_back(13);
  vec.push_back(2);
  vec.push_back(1);
  
  gnome(vec.begin(), vec.end()-1);
  
  std::copy(vec.begin(), vec.end(), std::ostream_iterator<int>(std::cout, " "));
}

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

CodeProject MVP for 2010 - who'd'a thunk it!

VeganFanatic12-Aug-10 8:56

12-Aug-10 8:56

here is the call routine

void RunGnomeSort(void) {
	size_t size = 10000;
	std::vector<int> data;
	data.resize(size);
	for (int i = 0; i < size; i++)
		data[i] = (int)rand();
	sort::gnome(data.begin(),data.end());
	//for (int i = 0; i < size; i++)
		//std::cerr << data[i] << std::endl;
	data.resize(0);
}

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Stuart Dootson12-Aug-10 9:16

12-Aug-10 9:16

Right - it's this line: sort::gnome(data.begin(),data.end());

Like in my example, that should be sort::gnome(data.begin(),data.end()-1);

data.end() points to the element after the last element in the vector, and the sort routine explicitly accesses the last parameter.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

CodeProject MVP for 2010 - who'd'a thunk it!

VeganFanatic12-Aug-10 9:20

12-Aug-10 9:20

Then I guess I need to change the function a tad, so that its a drop in comparable to std::sort.

I changed the code

while (pos < last) {

from <=

That has it working now, thanks for spotting that. Now I think I will post the code on Wilipedia as the algorithm is not super clear.

http://www.contract-developer.tk

ATL: WM_MOUSELEAVE

Supriya Tonape6-Aug-10 4:30

Supriya Tonape

6-Aug-10 4:30

hello

On WM_MOUSELEAVE message the below function OnMouseLeave() is not getting called... (however OnInitDialog() is getting called)

I have created a dialog box and wanted to call my function OnMouseLeave() on WM_MOUSELEAVE message. Declared a message map as below,

BEGIN_MSG_MAP(CMyClass)
MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
MESSAGE_HANDLER(WM_MOUSELEAVE, OnMouseLeave)
END_MSG_MAP()

any idea if am missing something ?

Thanks and Regards,
Supriya Tonape

Frank Seidler6-Aug-10 4:38

Frank Seidler

6-Aug-10 4:38

Hello,

this is a MS design feature. You need to call TrackMouseEvent prior to receive a WM_MOUSELEAVE-Message.

See: http://msdn.microsoft.com/en-us/library/ms645615%28VS.85%29.aspx for more info.

Kind regards

Frank

Sauro Viti6-Aug-10 4:46

Sauro Viti

6-Aug-10 4:46

Just for completeness, the best place where you could put the TrackMouseEvent function, is inside the handler of the WM_MOUSEENTER message Wink | ;)

Supriya Tonape9-Aug-10 2:25

Supriya Tonape

9-Aug-10 2:25

Thank you. Yes I am using the trackmouseevent in OnMouseLeave() method.. actually i just replaced message as "WM_MOUSEMOVE" and it started working.. but thanks much for the help.

Also I cud not find WM_MOUSEENTER message in respective .h file..

thanks and regards,
Supriya Tonape