C / C++ / MFC

Re: how do i use DeleteObject()...

2-Mar-02 21:44

do i use delete object like this to prevent resource leaks???

// Destructor
CBoard::~CBoard()
{
// Delete the object to prevent resource leaks
mpPen->DeleteObject();
mpFont->DeleteObject();

// Destroys all the pointers to all objects
delete mpPen;
delete mpFont;

for (int r = 0; r < MAXROW; r++)
for (int c= 0; c < MAXCOL; c++)
delete mpGrid[r][c];
}

or i can just destroy it by deleting it or do i have to release it before i delete it when i called it like this:

// Change the Font Height and Width to the values entered
void CBoard::SetFontSize(CDC* pDC, int Height, int Width)
{
mpFont = new CFont;
VERIFY(mpFont->CreateFont(Height,Width,0,0,0,0,0,0,0,0,0,0,
DEFAULT_PITCH|FF_DONTCARE,"Tictactoe"));

VERIFY(mpDefaultFont = pDC->SelectObject(mpFont));
}

anyways, can anyone tell me if i am doing it right or what i am doing can cause memory or resource leaks... well, thank you in advance for your help Smile | :)

John

Christian Graus2-Mar-02 21:44

Christian Graus

2-Mar-02 21:44

The most important step is selecting the original pen/brush/font into the DC before destroying it. OTherwise you will leak GDI resources and your program will eventually kill the graphics subsystem on any non-NT based OS.

You don't need to call DeleteObject before calling delete. Delete allows you to delete the handle being encapsulated without destroying the class object.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Re: how do i use DeleteObject()...

John Cruz2-Mar-02 21:57

2-Mar-02 21:57

Thanks for the help Christian. ill remember that Smile | :)

Texture filter in OpenGL

Mazdak2-Mar-02 19:30

Re: Texture filter in OpenGL

2-Mar-02 19:30

I have very basic question.I read some tutorials but didn't get one thing,I want to know what is "texture filters".I don't know what is it and what's they are good for?
Can anybody tell me about it in simple words?

thanks

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

alex.barylski2-Mar-02 22:55

alex.barylski

2-Mar-02 22:55

I'm surprised Christian hasn't answered you...? Christian where are you...?

Textures are the images you map to polygons, this I assume you know...filters are usually...ummm just that...filter certain content...

Graphics filters...in psp7 seem to allow you to apply special effects...IE 4.0+ supports a feature called Filters and Transitions which again apply certain effects to elements.

So it's my best reasoning that texture filters are probably filters you apply to images(textures) for a certian effect...like changing the alpha-factor (which I think is what gives textures semi-transluecency)

Yup...these are my guesses from my work with graphics...

Cheers!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: Texture filter in OpenGL

Mazdak2-Mar-02 23:23

Using Delimiter EOF :: C++

2-Mar-02 23:23

hmmm,thanks HockeyDude.

HockeyDude wrote:
I'm surprised Christian hasn't answered you...? Christian where are you...?

I was waiting for his answer too Wink | ;)

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

valikac2-Mar-02 19:26

valikac

2-Mar-02 19:26

Hi.

I am working on a small practice program for a C++ class. I need to implement a way to delimite using EOF. The user can break out of a while, for example, with ctrl-d (dos) or ctrl-z (unix).

What is the best way to implement something like that?

I have tried this:

while((num = cin.get()) != EOF) // from Deitel
{}

The above does not work.

Thanks,
Kuphryn

Re: Using Delimiter EOF :: C++

Mazdak2-Mar-02 19:29

2-Mar-02 19:29

I didn't use it in C++,but just guess,try this:

while(cin.get()!=EOF)
{
}

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

ATL doubt

Nish Nishant2-Mar-02 18:15

2-Mar-02 18:15

Hello

Say I am writing an ATL component.
Which are the various methods available to me to return a VB/ASP array?
From VB/ASP I should be able to do something like this :-

Set x = CreateObject("ABC.abx")
y=x.GetNiceLongArray()

for each t in y
   response.write t
next

Any ideas, help is hugely appreciated.
I think someone told me abt safe arrays, last week. But last 7 days I didnt touch this stuff again ...
Now that it's a nice sunday, I thought I might as well do some learning...

Nish

It's seven o'clock
On the dot
I'm in my drop top
Cruisin' the streets - Oh yeah
I got a real pretty, pretty little thing that's waiting for me

Mazdak2-Mar-02 19:21

2-Mar-02 19:21

Hi Nish:

public:
HRESULT FinalConstruct();
private:
std::vector(CComBSTR) m_vearray;--->I change this line because its like HTML tag,but you know the difference

Then add the implementation of FinalConstruct()

HRESULT CYourClass::FinalConstruct()
{
m_vearray.push_back(CComBSTR(L"Hello"));
return S_OK;
}

then add a property to your component with VARIANT * argument

STDMETHODIMP CYourclass::get_property(VARIANT * pVal)
{
VariantInit(pVal);
pVal->vt=VT_ARRAY|VT_BSTR;
SAFEARRAY *psa;
SAFEARRAYBOUND bounds=(m_vearray.size(),0);
psa=SafeArrayCreate(VT_BSTR,1,&bounds);

BSTR *bstrArray;
SafeArrayAccessData(psa,reiterpret_cast<void **>(&bstrArray));
std::vector(CComBSTR)::iterator it;--->change this line too
int i=0;
for(it=m_vearray.begin();it !=m_vearray.end();i++)
{
  bstrArray[i]=SysAllocString((*it).m_str);
}
SafeArrayUnaccessData(psa);
pVal->parray=psa;
return S_OK;
}

Is that what you want Nish?

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

Nish Nishant2-Mar-02 21:04

2-Mar-02 21:04

Mazdak wrote:
Is that what you want Nish?

Mazy

Hello Mazy

Thanks for that. But I wasnt looking for code snippets. Specially since most of it didnt make any sense to me. I have not spend too much time on ATL. Just a couple of hrs every week. Sometimes less than that.

From your post I understand I need to look into safe arrays.
I dont wanna use std::vector either.

So do you know any good intro stuff on safe arays.
The book I have [Inside ATL by Shephard and King] does not have a chapter on safe arrays Frown | :-(

Regards and thanks once again
Nish

It's seven o'clock
On the dot
I'm in my drop top
Cruisin' the streets - Oh yeah
I got a real pretty, pretty little thing that's waiting for me

Mazdak2-Mar-02 21:28

2-Mar-02 21:28

Nish [BusterBoy] wrote:
So do you know any good intro stuff on safe arays.

Hi Nish:

I don't have any intro about it,but some months ago,I found some articles about ATL at the link below,check it maybe you find something useful about ATL or safe array.

p2p.wrox.com

Nish [BusterBoy] wrote:
The book I have [Inside ATL by Shephard and King] does not have a chapter on safe arrays

I myself began ATL with "Beginning ATL3COM Programming by Richard Grimes" ,in this books some pages belong to safearray,the codes I used was from this book.I like this book because it goes in details of ATL.

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

Nish Nishant2-Mar-02 22:30

2-Mar-02 22:30

Thanks Mazy Smile | :)

Nish

It's seven o'clock
On the dot
I'm in my drop top
Cruisin' the streets - Oh yeah
I got a real pretty, pretty little thing that's waiting for me

Christian Graus2-Mar-02 21:41

Christian Graus

2-Mar-02 21:41

Nish [BusterBoy] wrote:
From your post I understand I need to look into safe arrays.

Yes, you do. I just did my first one of these on Friday, and read it in an .asp.

Nish [BusterBoy] wrote:
I dont wanna use std::vector either.

You can't anyhow, to impliment an automation compatible server, you need to stick to the object types defined by COM, not those specific to C++. However, why WOULDN'T you use vector ? Smile | :)

Nish [BusterBoy] wrote:
So do you know any good intro stuff on safe arays.
The book I have [Inside ATL by Shephard and King] does not have a chapter on safe arrays

Surely MSDN has some info ? The best ATL book I bought ( and I bought a lot ) was Creating lightweight components with ATL by Jonothan Bates. If you want to learn ATL, get this book. It has a half decent intro to STL in it, no match for a decent text, but an OK intro nonetheless.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Nish Nishant2-Mar-02 22:31

2-Mar-02 22:31

Christian Graus wrote:
You can't anyhow, to impliment an automation compatible server, you need to stick to the object types defined by COM, not those specific to C++.

Okay, then what's the ATL equivalent for std::vector ???

Nish

It's seven o'clock
On the dot
I'm in my drop top
Cruisin' the streets - Oh yeah
I got a real pretty, pretty little thing that's waiting for me

Christian Graus2-Mar-02 22:42

Christian Graus

2-Mar-02 22:42

Internally, you'd use vector, but I believe the answer is VARIANT, which has VT_ARRAY as one of it's types, which needs to be ORed with an actual type to make an array of.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Nish Nishant2-Mar-02 23:12

2-Mar-02 23:12

Dear CG,

Thanks for that. But I am now horrified by a new realization.
Read my new post for more info...

http://www.codeproject.com/script/comments/forums.asp?forumid=1647&select=124762#xx124762xx

Nish [still under shock]

It's seven o'clock
On the dot
I'm in my drop top
Cruisin' the streets - Oh yeah
I got a real pretty, pretty little thing that's waiting for me

pba_3-Mar-02 2:52

pba_

3-Mar-02 2:52

Check ATL's CSimpleArray / CSimpleMap. These templates are not documented, so you will have to take a look on the implementation Smile | :)

how to new a doc in MDI application in programme??

pba_3-Mar-02 3:13

pba_

3-Mar-02 3:13

If you want to enumerate a collection there is another mechanism more flexible and interesting then SAFEARRAY - take a look at enumeration interfaces ( IEnumXXX). ATL has support for this ( IEnumOnSTLImpl, etc) but you can do it by yourself very easily.

benben2-Mar-02 17:40

benben

2-Mar-02 17:40

hi:
how to new a doc in MDI application ?
Thanks
benben

Re: how to new a doc in MDI application in programme??

Roger Allen4-Mar-02 1:16

Roger Allen

4-Mar-02 1:16

If you have a pointer to the CDocTemplate for the document, you can create a new instance of it using

pDocTemplate->OpenDocumentFile(NULL) ;

If you need to do this from an existing doucment:

pDocTemplate = GetDocTemplate() ;
pDocTemplate->OpenDocumentFile(NULL) ;

or from anywhere else

CDocManager *pDocMan = AfxGetApp()->m_pDocManager ;
POSITION pos ;

pos = pDocMan->GetFirstDocTemplatePosition() ;
// note that if you have multiple doc types, you will have to find the correct one
// by iterating completely through the doc template list to the correct one
CDocTemplate *pDocTemplate = pDocMan->GetNextDocTemplate(pos) ;
pDocTemplate->OpenDocumentFile(NULL) ;

Roger Allen
Sonork 100.10016

If I'm not breathing, I'm either dead or holding my breath.
A fool jabbers, while a wise man listens. But is he so wise to listen to the fool?

Help writing a game tree for tictactoe

John Cruz2-Mar-02 17:02

Re: Help writing a game tree for tictactoe

2-Mar-02 17:02

can anyone help me design a game tree for tictactoe. i am trying to do the recursion for the AI of the tictactoe and i cant seem to get it write. i decided to write the game tree 1st but i can figure out how to write it. can anyone kindly help me do that? anyways, thank you very much.

alex.barylski2-Mar-02 18:32

alex.barylski

2-Mar-02 18:32

First of all...whats a game tree...?

Is this like a flowchart or something...?

What AI are you having problems with...determining a win with the active player or the computer making it's moves..?

Recursion will make your game logic IMO doubly hard...a simple double iteration loop would look much nicer on the eyes. Depending on how many times your recursion function is called, this could be very in-efficient. Unless i'm missing something...each time a function is called it pushe s it's params and locals onto a lifo stack, this could cause your stack to grow quite large i'd think.

Can you do it with a loop or MUST you use recursion...?

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: Help writing a game tree for tictactoe

John Cruz2-Mar-02 18:50