C / C++ / MFC

Re: Is it possible to construct a screen which can display the points of x, y and z axis by inputing 3 txt files by c++? [modified]

1-Apr-08 4:14

johndoelee wrote:
If C++ cannot make it, can other program like java achieve this task??

Please don't swear. Roll eyes | :rolleyes:

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

johndoelee1-Apr-08 4:58

johndoelee

1-Apr-08 4:58

Thank you for the replies form you guys.

Let me elaborate my request.

I wanna display a line which is constructed and connected by the first point to the last point which resembles animation. The most important thing is to show how the line is connected by points and the graph which shows x,y,z axis clearly.

In addition, the x, y, z coordinates of various points are stored in three txt files where each of the txt file contains the coordinates of one axis only.

Thank you very much!
John

modified on Saturday, April 5, 2008 10:16 AM

ListBox SDI SetFont

_chew1-Apr-08 3:09

_chew

1-Apr-08 3:09

Hi guys.

I'm new to MFC. I'm doing an SDI app with a ListBox on one pane. There are three panes on the app. I can't change the font style of the listbox control. Any idea on how to do that?

Regards,
_chew

David Crow1-Apr-08 3:30

David Crow

1-Apr-08 3:30

_cheewex wrote:
I can't change the font style of the listbox control.

Why not? What have you tried?

_cheewex wrote:
Any idea on how to do that?

What's wrong with the SetFont() method?

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

_chew1-Apr-08 5:57

_chew

1-Apr-08 5:57

I have tried these three methods so far...

// First way
CFont Font;

Font.CreateFont(12, // Height
0, // Width
0, // Escapement
0, // Orientation
FW_BOLD, // Weight
FALSE, // Italic
TRUE, // Underline
0, // StrikeOut
ANSI_CHARSET, // CharSet
OUT_DEFAULT_PRECIS, // OutPrecision
CLIP_DEFAULT_PRECIS, // ClipPrecision
DEFAULT_QUALITY, // Quality
DEFAULT_PITCH | FF_SWISS, // PitchAndFamily
"Arial")); // Facename

pListBox->SetFont(&Font);

// Second way
CFont Font;
LOGFONT lfLogFont;

memset(&lfLogFont, 0, sizeof(lfLogFont));

lfLogFont.lfHeight = 12; // 12-pixel-height
lfLogFont.lfWeight = FW_BOLD; // Bold
lfLogFont.lfUnderline = TRUE; // Underlined

strcpy(lfLogFont.lfFaceName, "Arial"); // Arial

Font.CreateFontIndirect(&lfLogFont);

pListBox->SetFont(&Font);

// Third way
CFont Font;
LOGFONT lfLogFont;

memset(&lfLogFont, 0, sizeof(lfLogFont));

lfLogFont.lfHeight = 120; // 12-pixel-height
lfLogFont.lfWeight = FW_BOLD; // Bold
lfLogFont.lfUnderline = TRUE; // Underlined

strcpy(lfLogFont.lfFaceName, "Arial"); // Arial

Font.CreatePointFontIndirect(&lfLogFont);

pListBox->SetFont(&Font);

Mark Salsbery1-Apr-08 6:14

Mark Salsbery

1-Apr-08 6:14

Try using a font that doesn't go out of scope.

i.e. move your CFont object to someplace its lifetime lasts longer than the control Smile | :)

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

David Crow1-Apr-08 6:15

David Crow

1-Apr-08 6:15

It appears that the CFont object is going out of scope. It must exist at least as long as the CListBox object. Can you confirm or deny?

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

_chew1-Apr-08 17:01

_chew

1-Apr-08 17:01

I think it's not going out of scope. I noticed that it responded to size change only. I was not able to distinguish the change before because I just copied the size from MSDN. When I changed it significantly, it did change with respect to size but not with the font style ("Tahoma"). Don't know why it won't change.

Mark Salsbery1-Apr-08 19:22

Mark Salsbery

1-Apr-08 19:22

Where are you calling the code you showed?

All those CFont objects look local to me, thus they are probably going out of scope and being destroyed,
before the control even has a chance to reflect the change I reckon..

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Hamid_RT7-Apr-08 3:37

Hamid_RT

7-Apr-08 3:37

Can you show your code?

auto_ptr array

George_George1-Apr-08 0:50

1-Apr-08 0:50

Hello everyone,

I have tried to initialize an auto_ptr array, but failed. My C++ Programming Language book does not contain a sample about how to initialize an auto_ptr array.

(not an auto_ptr pointing to an array, which is not legal)

Any solutions?

#include <memory>

using namespace std;

int main()
{
	auto_ptr<int[]> pi (new int[10]); // compile error
	
	auto_ptr<int> pi (new int[10]); // compile error
	
	return 0;
}

thanks in advance,
George

_AnsHUMAN_ 1-Apr-08 0:59

_AnsHUMAN_

1-Apr-08 0:59

Like this :
auto_ptr<int> p(new int(10));

George_George1-Apr-08 1:41

1-Apr-08 1:41

Hi _AnShUmAn_,

It is not correct code. Because the destructor of auto_ptr will use delete other than delete[]. And it will lead to memory leak.

Any ideas or comments?

regards,
George

CPallini1-Apr-08 1:55

1-Apr-08 1:55

George_George wrote:
It is not correct code.

TRUE. Actually the code is correct, but is not a solution for your OP one. Smile | :)

George_George wrote:
Because the destructor of auto_ptr will use delete other than delete[]. And it will lead to memory leak.

FALSE.

It allocates just 1 integer (and initialise it to 10) hence no memory leaks after delete.

BTW: no compiler error for the code below

auto_ptr<int[10]> pi(new int[10]);

George_George1-Apr-08 2:03

1-Apr-08 2:03

Hi, CPallini,

1.

CPallini wrote:
George_George wrote:
Because the destructor of auto_ptr will use delete other than delete[]. And it will lead to memory leak.

FALSE. It allocates just 1 integer (and initialise it to 10) hence no memory leaks after delete.

I am confused. We are talking about destructor of auto_ptr? Why do you say "allocates"?? Could you provide more description please? Smile | :)

CPallini wrote:
BTW: no compiler error for the code below

auto_ptr<int[10]> pi(new int[10]);

No, I have compile errors in MSVC 2008.

1>Compiling...
1>main.cpp
1>d:\visual studio 2008\projects\test0401\test0401\main.cpp(7) : error C2664: 'std::auto_ptr<_Ty>::auto_ptr(_Ty (*)) throw()' : cannot convert parameter 1 from 'int *' to 'int (*)[10]'
1>        with
1>        [
1>            _Ty=int [10]
1>        ]
1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

regards,
George

CPallini1-Apr-08 2:17

1-Apr-08 2:17

George_George wrote:
I am confused. We are talking about destructor of auto_ptr? Why do you say "allocates"?? Could you provide more description please?

I report below _AnShUmAn_ code for reference.

auto_ptr<int> p(new int(10));

In the above expression, the new operator allocates one int and initialise it with the number 10.

George_George wrote:
No, I have compile errors in MSVC 2008.

Well, I have VS2005, and no errors here. However I've to admit I overlooked the following (serious) warning:

warning C4156: deletion of an array expression without using the array form of 'delete'; array form substituted
[...].

George_George1-Apr-08 2:22

1-Apr-08 2:22

Thanks CPallini,

1.

--------------------
deletion of an array expression without using the array form of 'delete'
--------------------

Means auto_ptr will use delete other than delete[] is destructor of auto_ptr?

2.

--------------------
array form substituted
--------------------

What means "array form substituted"?

regards,
George

CPallini1-Apr-08 2:28

1-Apr-08 2:28

George_George wrote:
Means auto_ptr will use delete other than delete[] is destructor of auto_ptr?

I think so.

George_George wrote:
What means "array form substituted"?

as the compiler output window shows

_Ty=int [10]

i.e. internal type _Ty (blindly) substitutes an array form.

Your example, IMHO shows:
(1) The std::auto_ptr though helpful is not a panacea.
(2) VC++ compiler is smart.
Smile | :)

George_George1-Apr-08 2:54

1-Apr-08 2:54

Thanks CPallini,

1.

The compiler deduce _Ty,

_Ty=int [10]

is because of the following code?

auto_ptr<int[10]>

2.

In your sample, compiler will make

A. one auto_ptr object wrapps an int array on heap;
or
B. ten auto_ptr objects and each object wrapps an int on heap?

regards,
George

CPallini1-Apr-08 3:01

1-Apr-08 3:01

1. Yes.
2. A.
Smile | :)

George_George1-Apr-08 3:16

1-Apr-08 3:16

Thanks CPallini,

I read the compile error message you posted,

--------------------
warning C4156: deletion of an array expression without using the array form of 'delete'
--------------------

I think your code will have memory leak potentially? Because delete other than delete[] will work on the array?

regards,
George

CPallini1-Apr-08 4:09

1-Apr-08 4:09

George_George wrote:
I think your code will have memory leak potentially? Because delete other than delete[] will work on the array?

The delete syntax will be used (insted of the delete [] one).
About potential memory leaks, from MSDN [^]

The following two cases produce undefined results: using the array form of delete (delete [ ]) on an object and using the nonarray form of delete on an array.

Smile | :)

George_George1-Apr-08 4:19

1-Apr-08 4:19

You mean your code will cause undefined behavior? CPallini?

regards,
George