Re: delete zero out its operand - C / C++ / MFC Discussion Boards

Re: How to store/load several files together when serialize?

CPallini26-Mar-08 6:36

26-Mar-08 6:36

If you really need to store multiple file into yor unique one, you have to copy every file content (possibly each one prefixed by its length).
You may wrap this behaviour into a serializable class (you may call it CFile, oops, no, wait a moment...).
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

Strange error using Case statement

piul26-Mar-08 5:14

piul

26-Mar-08 5:14

I'm getting a strange error...
if I write:

if (uType == ANNEAL)
{
  CAnneal * pOrigAnn = dynamic_cast<CAnneal *> (pOrigItem)	;
  if(pOrigAnn != NULL)
  {
     CAnneal * pAnneal = new CAnneal();
  }
...

Everything's fine. But, if I want to use a case instead of an if

switch (uType)
{
  case ANNEAL:
     CAnneal * pOrigAnn = dynamic_cast&lt;CAnneal *&gt; (pOrigItem)	;
     if(pOrigAnn != NULL)
    {
       CAnneal * pAnneal = new CAnneal();
    }
    break;
  case WHATEVER:
...

I get an error that says "initialization of 'pOrigAnn' is skipped by 'default' label" ... "See declaration of pOrigAnn" Confused | :confused:

Re: Strange error using Case statement

CPallini26-Mar-08 5:32

CPallini

26-Mar-08 5:32

Beacause you've not included your code inside a block and pOriginAnn is the whole switch block (while its assignment happens only in ANNEAL case.
You may change it to

switch (uType)
{
  case ANNEAL:
    {
       CAnneal * pOrigAnn = dynamic_cast<CAnneal *> (pOrigItem)	;
       if(pOrigAnn != NULL)
      {
         CAnneal * pAnneal = new CAnneal();
      }
    }
    break;
  case WHATEVER:
...

Re: Strange error using Case statement

piul26-Mar-08 5:41

piul

26-Mar-08 5:41

Interesting...
Thank you!!

Re: Strange error using Case statement

rp_suman26-Mar-08 5:49

rp_suman

26-Mar-08 5:49

Hi,

So you got the problem..

Thanks,
Suman

Re: Strange error using Case statement

rp_suman26-Mar-08 5:35

rp_suman

26-Mar-08 5:35

Hi,

Is there any other access of "pOrigAnn" outside of "case ANNEAL" like:

piul wrote:

switch (uType){
case ANNEAL:
CAnneal * pOrigAnn = dynamic_cast<CAnneal *> (pOrigItem);
if(pOrigAnn != NULL){
CAnneal * pAnneal = new CAnneal();
}
break;
case WHATEVER:...
...
break;
default:
...
}
//access pOrigAnn

or somewhere else?

Thanks,
Suman

delete zero out its operand

George_George26-Mar-08 5:09

George_George

26-Mar-08 5:09

Hello everyone,

A little confused after reading C++ FAQ, "Why doesn't delete zero out its operand?"

http://www.research.att.com/~bs/bs_faq2.html#delete-zero

I think the reason why delete can not zero out its operand is because delete can be operate on rvalue, like

delete f(x);

And we can not assign zero to the rvalue (i.e. delete's operand). My understanding correct?

thanks in advance,
George

Re: delete zero out its operand

CPallini26-Mar-08 5:24

CPallini

26-Mar-08 5:24

Yes, Bjarne states that clearly.
Smile | :)

Re: delete zero out its operand

George_George26-Mar-08 17:14

George_George

26-Mar-08 17:14

Thanks CPallini,

I think you agree with my understanding. Smile | :)

regards,
George

c++ algorithm to find point inside polygon or not

rp_suman26-Mar-08 5:04

rp_suman

26-Mar-08 5:04

Hi,

I am looking for algorithm which will find the given point is inside of a given polygon(a triangle) or not.
Which will work for coordinate in -ve and +ve direction.

Best Regards,
Suman

Re: c++ algorithm to find point inside polygon or not

BadKarma26-Mar-08 5:53

BadKarma

26-Mar-08 5:53

If you can walk over the lines polygon you should find the point always on the same side either left or right.

Otherwise check out this page[^]

codito ergo sum

Re: c++ algorithm to find point inside polygon or not

CPallini26-Mar-08 5:55

CPallini

26-Mar-08 5:55

You don't like PtInRegion and CreatePolyRegion functions, do you?

Re: c++ algorithm to find point inside polygon or not

SandipG 26-Mar-08 11:18

SandipG

26-Mar-08 11:18

Re: c++ algorithm to find point inside polygon or not

BadKarma26-Mar-08 21:31

BadKarma

26-Mar-08 21:31

The OP did ask for algorithms and not the functions Poke tongue | ;-P

Maybe i should redirected him, my bad $Shucks | :-\$

To be honest I didn't think of those functions. It has been a long time since I did some GUI stuff.
So thanks for the BrainRefresh Big Grin | :-D

codito ergo sum

Re: c++ algorithm to find point inside polygon or not

rp_suman26-Mar-08 21:49

rp_suman

26-Mar-08 21:49

Hi,

Thanks for help..

How to create the region when the points are not in order and we need to fill the complete region by connecting outermost points using CreatePolyRegion()?

Thanks,
Suman

Re: c++ algorithm to find point inside polygon or not

CPallini26-Mar-08 22:18

CPallini

26-Mar-08 22:18

Aren't you able to order the points? Is the polygon convex?
Try also the Graphics forum [^].

Re: c++ algorithm to find point inside polygon or not

rp_suman26-Mar-08 22:47

rp_suman

26-Mar-08 22:47

CPallini wrote:
Is the polygon convex?

The polygon can be of any type.
The points may not be in order most of the time.

I will post in Graphics section

Thanks for help!!

Best Regards,
Suman

Re: c++ algorithm to find point inside polygon or not

Saurabh.Garg27-Mar-08 0:02

Saurabh.Garg

27-Mar-08 0:02

You need Convex Hull of points to find a polygon including all points.

-Saurabh

Re: c++ algorithm to find point inside polygon or not

rp_suman2-Apr-08 21:55

rp_suman

2-Apr-08 21:55

Saurabh.Garg wrote:
You need Convex Hull of points to find a polygon including all points.

Hi,

Thanks for the help.

Is there function to get convex hull of points from set of polygon points which is not in order.

Thanks,
Suman

--
"Programming is an art that fights back!"

msflexgrid pointer

_chew26-Mar-08 4:31

_chew

26-Mar-08 4:31

hi guys. just started with visual c++ mfc. im currently making an SDI app with two splitters. 1 vertical and 1 horizontal. i used the SDI (windows explorer) wizard but added one horizontal splitter. leftview is a treeview control, lower right is listview control. for the upper right, the msflexgrid control. i used the "add to project-components and controls-registered activex comps" for the flexgrid. how can i obtain a pointer to my flexgrid (for manipulation)? like when i'll click on a tree node, i want to do something with my flexgrid.

any help will much be appreciated. and sorry for my english...thanks.

Re: msflexgrid pointer

rp_suman26-Mar-08 4:44

rp_suman

26-Mar-08 4:44

Hi,

Hope this will be helpful: Using the Flexgrid in VC++[^]

Best Regards,
Suman

Re: msflexgrid pointer

_chew26-Mar-08 5:02

_chew

26-Mar-08 5:02

thanks Suman. but i think its only applicable to dialog based apps, im not sure. i dont have a form where i could put/draw/drag the flexgrid control to, since its SDI.

regards,
_chew

Re: msflexgrid pointer

rp_suman26-Mar-08 5:18

rp_suman

26-Mar-08 5:18

Hi,

How you are creating flxgrid in your application?
Are you creating in runtime?

Depending on that method we will try to get pointer.

Thanks,
Suman

Re: msflexgrid pointer...another problem

_chew26-Mar-08 6:05

_chew

26-Mar-08 6:05

Now I've got a problem. I've got an assertion error...

If i'll ignore the assertion message, the app will continue to load showing only two columns and two rows in the flexgrid area.

What i did was i added a class that inherits CMSFlexGrid.
This is the overriden function:

BOOL CGrid::PreCreateWindow(CREATESTRUCT &cs)
{
return CMSFlexGrid::PreCreateWindow(cs);
}

I tried to follow the ways the treeview and listview ctrls are attached to the other panes of my app. Im just confused why flexgrid could not be drawn in the upper right pane.

Thanks,
_chew

Re: msflexgrid pointer...another problem

rp_suman26-Mar-08 14:58

rp_suman

26-Mar-08 14:58

Hi,

Check if you can use CreateControl()[^]

Best Regards,
Suman

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