Re: Need help with multi-dim arrays please - C / C++ / MFC Discussion Boards

RChin24-Sep-03 8:46

24-Sep-03 8:46

I think this relates to your problem, but may not solve it:

http://support.microsoft.com/default.aspx?scid=kb;en-us;242577[^]

It basically describes the problem whereby the UI menu updates will not work for dialog based application.

I Dream of Absolute Zero

Re: Dialog menu problem...

LukeV24-Sep-03 9:49

LukeV

24-Sep-03 9:49

Found the problem... I was using ModifyMenu to change the menu item's text, and it was setting the ID to 0.

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Need help with multi-dim arrays please

Flack24-Sep-03 7:51

Flack

24-Sep-03 7:51

In a header file of one of my classes I have a private two dim array,

<br />
double V[][6] = {<br />
      {-.01,0,0, -.2,-.2,1},  // POINT AND NORMAL<br />
      {.1,0,0, .2,-.2,1},<br />
      {0,.11,0,  -.2,.2,1},<br />
      {.08,.09,0,  .2,.2,1}<br />
   };<br />

but this gives me a compiler error. It says "syntax error : '{'" and
"unexpected token(s) preceding '{'; skipping apparent function body".
Does anyone know why? All I want to do is declare and initialize it.

Also, lets say I have a 3-dim array, (which I cant initialize either until I fix my first problem)

<br />
double polygon[][][] = {<br />
      { V[0], V[1], V[2] },<br />
      { V[1], V[2], V[3] }<br />
   };<br />

and I need a for loop to go thru polygon. I want to do something like:

<br />
for (int n = 0 ; n < polygon.length ; n++)<br />
  for (int i = 0 ; i < polygon[n].length ; i++) {<br />
    for (int k = 0 ; k < 3 ; k++)<br />
       normal[k] = polygon[n][i][k+3];<br />

What do I replace the bold & underlined with? Would it be sizeof(polygon)/sizeof(polygon[0]) for the outer loop and sizeof(polygon[0])/sizeof(polygon[0][0]) for the inner?

This stuff confuses me.

Thanx for the help,
-Flack

Re: Need help with multi-dim arrays please

David Crow24-Sep-03 8:20

David Crow

24-Sep-03 8:20

I got no errors with your two-dimensional array.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Need help with multi-dim arrays please

Flack24-Sep-03 8:34

Flack

24-Sep-03 8:34

Here is the entire header file:

<br />
/*<br />
   Extremely simple example of zbuffer algorithm<br />
*/<br />
#include <windows.h><br />
#include <math.h><br />
#include "Pix.h"<br />
<br />
class ZBuffer1 {<br />
// THE SCENE<br />
<br />
	private:<br />
	// ALL VERTICES IN THE SCENE<br />
	double V[][6] = {<br />
        {-.01,0,0, -.2,-.2,1},  // POINT AND NORMAL<br />
        {.1,0,0, .2,-.2,1},<br />
        {0,.11,0,  -.2,.2,1},<br />
        {.08,.09,0,  .2,.2,1}<br />
        };<br />
<br />
	// ALL POLYGONS IN THE SCENE - THESE REFER TO THE VERTICES<br />
	double polygon[3][3][3];<br />
<br />
	// ALL LIGHT SOURCE DIRECTION VECTORS IN THE SCENE<br />
	double L[1][3];<br />
<br />
	double rgb[3];<br />
	double p[30][7]; // TEMPORARY STORAGE FOR SHADED PROJECTED POLYGON<br />
<br />
	// THE RENDERER<br />
	double FAR_Z; // BACKGROUND Z<br />
	double * zbuffer;<br />
	double normal[3];<br />
<br />
	int W, H;<br />
<br />
	// INITIALIZE EVERYTHING ON START<br />
	void init();<br />
<br />
	// CLEAR THE ZBUFFER AND IMAGE<br />
	void clearZbuffer();<br />
<br />
	// PROJECT ONE {X,Y,Z,Nx,Ny,Nz} VERTEX ONTO THE IMAGE PLANE,<br />
	// AND SHADE IT, TO CREATE A {Px,Py,Pz,Red,Green,Blue} VECTOR<br />
	void projectVertex(double pt[], double p[]);<br />
<br />
	// VERY ELEMENTARY VERTEX SHADER (JUST A PLACE-HOLDER)<br />
	// THIS SHOULD BE REPLACED BY A TRUE PHONG SHADING ALGORITHM<br />
	void doShading(double pt[], double rgb[]);<br />
<br />
	// DISPLAY ONE POLYGON<br />
	void displayPolygon(double polygon[][3]);<br />
<br />
    // GENERIC UTILITY ROUTINES<br />
<br />
	// NORMALIZE A VECTOR<br />
	void normalize(double v[]);<br />
<br />
	// LINEAR INTERPOLATION<br />
	double lerp(double t, double a, double b) {return a + t * (b - a);}<br />
<br />
	// CONVERT A FLOATING POINT VALUE INTO A 0..255 INTEGER<br />
	int f2i(double t) {return max(0, min(255, (int)(255 * t)));}<br />
<br />
	public:<br />
	Pix pix;<br />
<br />
	ZBuffer1(int, int);<br />
	// THIS IS CALLED EVERY FRAME TO RENDER THE IMAGE<br />
	void setPix();<br />
};<br />

I try to compile and still get an error on the underlined line:
zbuffer1.h(14) : error C2059: syntax error : '{'
zbuffer1.h(14) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body

I dont know what Im doing wrong.

Re: Need help with multi-dim arrays please

David Crow24-Sep-03 9:04

David Crow

24-Sep-03 9:04

Flack wrote:
I dont know what Im doing wrong.

You are trying to initialize that array within the class itself. Try this:

class ZBuffer1
{
private:
    double V[][6];
public:
    ZBuffer1();
};
 
ZBuffer1::ZBuffer1()
{
    V[0][0] = -0.01;
    V[0][1] =  0.0;
    V[0][2] =  0.0;
    V[0][3] = -0.2;
    V[0][4] = -0.2;
    V[0][5] =  1.0;
 
    V[1][0] =  0.1;
    V[1][1] =  0.0;
    V[1][2] =  0.0;
    V[1][3] =  0.2;
    V[1][4] = -0.2;
    V[1][5] =  1.0;
 
    V[2][0] =  0.0;
    V[2][1] =  0.11;
    V[2][2] =  0.0;
    V[2][3] = -0.2;
    V[2][4] =  0.2;
    V[2][5] =  1.0;
 
    V[3][0] = 0.08;
    V[3][1] = 0.09;
    V[3][2] = 0.0;
    V[3][3] = 0.2;
    V[3][4] = 0.2;
    V[3][5] = 1.0;
}

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Need help with multi-dim arrays please

JWood24-Sep-03 8:39

JWood

24-Sep-03 8:39

I think you have to first accept that this is not very easy to do in C/C++. A 2D array is an array of pointer to more arrays. In a declaration you can only have one unknown dimension []. So your second example will not compile. The first one might be an error related to

The rest must be specified. V is a pointer to a pointer, V[n] is a pointer and v[n][m] is a value. The [m] operator is saying advance i + k*m spaces to obtain the location.

You need to either dynamically allocate this with multiple news or allocs, or use constants to create the space in memory in the first place, so it is far easier just to store the dimensions in an integer and use this in your loops.

J.
----------------------------

Re: Need help with multi-dim arrays please

John M. Drescher24-Sep-03 15:08

John M. Drescher

24-Sep-03 15:08

JWood wrote:
You need to either dynamically allocate this with multiple news or allocs, or use constants to create the space in memory in the first place, so it is far easier just to store the dimensions in an integer and use this in your loops.

Or use C++.. vectors

John

Multiple lines in a static text control?

b_girl24-Sep-03 7:23

b_girl

24-Sep-03 7:23

Hey.

I was wondering if there was any way to get more than one line of text to appear in a static text control? I tried just putting a \n where I want the new line to start, but then any text after that is invisible.

So, I guess what I'm asking, is how do I turn:
43 text
into:
43
text

without using 2 separate static text boxes? (is this possible?)

Re: Multiple lines in a static text control?

Michael P Butler24-Sep-03 7:39

Michael P Butler

24-Sep-03 7:39

Hmm, what you describe should work. Your static control is large enough to show multiple lines?

43\ntext

Michael

'Curiosity's always been my downfall' - The Doctor: The Caves of Androzani

Re: Multiple lines in a static text control?

b_girl24-Sep-03 7:49

b_girl

24-Sep-03 7:49

*ahem*

thanks. stupid mistake. it was only large enough for one line, not both. haha. sorry!!!

Quickie question re char buffers

NewportKarl24-Sep-03 7:21

NewportKarl

24-Sep-03 7:21

Assuming a declaration of a character buffer:

char MyBuffer[10];

Will the following two statements produce the same results?

MyBuffer[5] = "x";

char* pMyBuffer = &MyBuffer;
pMyBuffer = pMyBuffer + 5;
*pMyBuffer = "x";

Thanks for your help,

Re: Quickie question re char buffers

Ravi Bhavnani24-Sep-03 7:55

Ravi Bhavnani

24-Sep-03 7:55

I think you meant 'x' and not "x". Smile | :)

Also, you're assuming the size of a character is 1 byte (which is true for non Unicode/MBCS systems). Finally, I would initialize pMyBufferwrite like this (just to be explicit):

char* pMyBuffer = & (MyBuffer[0]);
...

Apart from this, yes.

/ravi

Let's put "civil" back in "civilization"
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Re: Quickie question re char buffers

Alvaro Mendez24-Sep-03 9:07

Alvaro Mendez

24-Sep-03 9:07

Ravi Bhavnani wrote:
Also, you're assuming the size of a character is 1 byte (which is true for non Unicode/MBCS systems).

AFAIK a char in C/C++ is always one byte in size. And his example uses chars not TCHARs.

Regards,
Alvaro

Hey! It compiles! Ship it.

Re: Quickie question re char buffers

Ravi Bhavnani24-Sep-03 9:14

Ravi Bhavnani

24-Sep-03 9:14

Alvaro Mendez wrote:
AFAIK a char in C/C++ is always one byte in size.

Good point! Blush | :O

I've been spending (way) too much time moving between CStrings, char* and XMLCh in my (Unicode) app. My mind is in a fog (i.e. more than usual).

/ravi

Let's put "civil" back in "civilization"
Home | Articles | Freeware | Music
ravib@ravib.com

Re: Quickie question re char buffers

Alvaro Mendez24-Sep-03 9:30

Alvaro Mendez

24-Sep-03 9:30

Ravi Bhavnani wrote:
I've been spending (way) too much time moving between CStrings, char* and XMLCh in my (Unicode) app.

Perfectly understandable. I don't remember the last time I used char in an MFC app. It's practically extinct. Smile | :)

Regards,
Alvaro

Hey! It compiles! Ship it.

Re: Quickie question re char buffers

Alvaro Mendez24-Sep-03 9:02

Alvaro Mendez

24-Sep-03 9:02

Not the way you have them. Here's how:

char MyBuffer[10];

// 1
MyBuffer[5] = 'x';

// 2
char* pMyBuffer = MyBuffer;
pMyBuffer = pMyBuffer + 5;
*pMyBuffer = 'x';

Regards,
Alvaro

Hey! It compiles! Ship it.

Re: Quickie question re char buffers

Karl Fetterhoff25-Sep-03 7:06

Karl Fetterhoff

25-Sep-03 7:06

Thank you! You guys are a great help.

Setup API

Laroo24-Sep-03 7:03

Laroo

24-Sep-03 7:03

How can I use the Setup API functions with a INF_STYLE_OLDNT inf file to cause the PnP Manager to kick in? If I need to use a INF_STYLE_WIN4 inf file, what are the key Setup API functions? Confused | :confused:

GetOpenFileName filter

Jason Henderson24-Sep-03 6:05

Jason Henderson

24-Sep-03 6:05

I have a static filter using something like this:

TCHAR* tcFilter = _T("Word Document\0*.DOC\0Excel Document\0*.XLS\0");

What I really need is a dynamic filter where I can remove or add file types to it.

TCHAR* tcFilter = NULL;

if (IsWordInstalled())
   // add it to the filter

etc.

Any suggestions on how I can do this? That '\0' delimiter really throws me for a loop.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
blog | articles

Re: GetOpenFileName filter

David Crow24-Sep-03 8:26

David Crow

24-Sep-03 8:26

I think you'll need to use std::string to handle the embedded '\0' characters.

Otherwise, you'll have to get tricky with the memcpy() function.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: GetOpenFileName filter

valikac24-Sep-03 9:18

valikac

24-Sep-03 9:18

Correct.

One solution is memcpy().

Kuphryn

Re: GetOpenFileName filter

Neville Franks24-Sep-03 10:29

Neville Franks

24-Sep-03 10:29

This works for me:

CString strFilter;
strFilter += ...
strFilter += (TCHAR)'\0';   // last string
dlgFile.m_ofn.lpstrFilter = strFilter;

Neville Franks, Author of ED for Windows. Free Trial at www.getsoft.com

Re: GetOpenFileName filter

Jason Henderson24-Sep-03 10:46

Jason Henderson

24-Sep-03 10:46

Would that handle multiple filters separated by '\0'?

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
blog | articles

Re: GetOpenFileName filter

Neville Franks24-Sep-03 10:48

Neville Franks

24-Sep-03 10:48

Jason Henderson wrote:
Would that handle multiple filters separated by '\0'?

Yes. You only need the \0\0 at the end from memory. Anyway this is how I do it in ED (see sig) to dynamically build the file types list.

Neville Franks, Author of ED for Windows. Free Trial at www.getsoft.com

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