C / C++ / MFC

Re: problem with trivial MFC app

15-Mar-03 9:06

I am kind of partial to "Inside Visual C++" by Kruglinski.

I have found that the best way to learn MFC is by doing. I have never learned much from reproducing book examples. I came from a C, Basic, FORTRAN, assembly language background. I learned the most by taking one of my old programs and making a MFC application out of it. I already knew how the meat of the program worked, so I could just concentrate on the GUI interface. I would use the programming books I bought (I own quite a few) and use the coding examples that applied to the program I was writting.

It may not be the best way to learn MFC, but it worked for me.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Anonymous13-Mar-03 10:55

Anonymous

13-Mar-03 10:55

There is no such thing as a "trival MFC" app.
That's why it is EOL;P

extracting flags from an integer

Kuniva13-Mar-03 6:24

Kuniva

13-Mar-03 6:24

I have an integer. For example my integer is 2147483712.
Now in hex form this is: 0x80000040

Now i need this system that works with "flags", flags as in a property that can be given to an object (what kind of object or whatever is beside the point). For example:

Property name HEX DEC

Property1 0x1 1
Property2 0x2 2
Property3 0x4 4
Property4 0x8 8
Property5 0x10 16
Property6 0x20 32
... and so on till
Property32 0x80000000 2147483648

So the object can have different properties which are put together into a single integer like this:

For example an object has properties 7 and 32 so the integer is 2147483712 as mentioned before. My question is, how do parse this, how do i get the individual properties from the integer, there must be an algorithm for this but i can't think of it.. (i never was very good at maths). So can anyone help me?

Thanks

Kuniva
--------------------------------------------

Hesham Amin13-Mar-03 6:54

Hesham Amin

13-Mar-03 6:54

Hi..
the good news is that you don't need to be good at math Smile | :)

use bitwise and operator &

msdn explains it better than me:
The bitwise-AND operator compares each bit of its first operand to the corresponding bit of its second operand. If both bits are 1, the corresponding result bit is set to 1. Otherwise, the corresponding result bit is set to 0.

so if you need to check the first bit (the first boolean property) use :
if(intVar & 1)
to check the second use :
if(intVar & 2)
etc..
so you compere with 1,2,4,8 etc ..
got it ?

Gary Kirkham13-Mar-03 6:55

13-Mar-03 6:55

You can check the flag with a logical AND like this

if(flag & Property32)

if the if statement returns true then the flag was set if it returns false (0) then the flag wasn't set.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Hesham Amin13-Mar-03 7:11

Hesham Amin

13-Mar-03 7:11

ok..
small correction : logical AND is &&
& is a bitwise operator Smile | :)

System Variables and PATH

Nitron13-Mar-03 8:11

Nitron

13-Mar-03 8:11

I'm sure this[^] can help! Big Grin | :-D

- Nitron

"Those that say a task is impossible shouldn't interrupt the ones who are doing it." - Chinese Proverb

Brian Delahunty13-Mar-03 5:53

Brian Delahunty

13-Mar-03 5:53

Hey Guys,

Just wondering if there is a quick and easy way [Other that using the Registry] to add System Variables and to add to the PATH.

e.g. Smile | :)

Adding BOB_RULES as a system variable and pointing it to c:\cp
and adding %BOB_RULES%\soapbox to the PATH

???
Green Alien | [Alien]

Thanks in advance lads Smile | :)

Regards,
Brian Dela Rose | [Rose]

Run naked in the snow until you're sweating like a stuck pig and can't seem to catch your breath. When the flu becomes pneumonia, they can cure that with a shot. - Roger Wright

Doubles to Strings for Edit Box Output

Brent Lamborn13-Mar-03 5:18

13-Mar-03 5:18

I'm writing a graphing program that draws x- and y- axis in a picture box and I want to label some of the hash marks. I cheated a little and used read only edit controls for the labels. My problem is this - I need to convert the array of labels (doubles) to an array of strings so that I can send them to the edit controls for display in the picture box. I've tried the CString.Format function and ToString function and even _gcvt but I can't seem to get any of them to do what I want. Can anyone help?

Here my button click event that is supposed to handle this:

void CGraphView::OnBnClickedBtnplot()<br />
{<br />
<br />
	double* Labels;<br />
<br />
	GetDlgItem(IDC_PICT)->GetWindowRect(pictRect);<br />
	ScreenToClient(pictRect);<br />
<br />
	//Labels [1 - 26] (one for each hash mark)<br />
	//Don't use all of them though<br />
	Labels = GetLabelVals();<br />
<br />
	SetDlgItemText(IDC_EDITINTERSECT, "INT"); <br />
	SetDlgItemText(IDC_EDITX1, str); <br />
	SetDlgItemText(IDC_EDITX2, "x2"); <br />
	SetDlgItemText(IDC_EDITX3, "x3"); <br />
	SetDlgItemText(IDC_EDITX4, "x4");<br />
	SetDlgItemText(IDC_EDITX5, "x5"); <br />
	SetDlgItemText(IDC_EDITY1, "y1");<br />
	SetDlgItemText(IDC_EDITY2, "y2"); <br />
	SetDlgItemText(IDC_EDITY3, "y3");<br />
<br />
	InvalidateRect(pictRect);<br />
}

Instead of the "x1...y3" I want the label strings to go in.
Any help would be appreciated!

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra

Gary Kirkham13-Mar-03 7:01

13-Mar-03 7:01

Why doesn't CString.Format do what you want...it will give you a formatted string. If you want an array of strings then check out CStringArray.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn13-Mar-03 8:52

13-Mar-03 8:52

Would it then look like this?

void CGraphView::OnBnClickedBtnplot()<br />
{<br />
<br />
	CStringArray strings;<br />
	strings.SetSize(26);<br />
	double* Labels;<br />
<br />
	GetDlgItem(IDC_PICT)->GetWindowRect(pictRect);<br />
	ScreenToClient(pictRect);<br />
<br />
	//Labels [1 - 26] (one for each hash mark)<br />
	//Don't use all of them though<br />
	Labels = GetLabelVals();<br />
<br />
	strings[1].Format("%.3d\n", Labels[1]);<br />
<br />
	SetDlgItemText(IDC_EDITINTERSECT, "INT"); <br />
	SetDlgItemText(IDC_EDITX1, strings[1]); <br />
	SetDlgItemText(IDC_EDITX2, "x2"); <br />
	SetDlgItemText(IDC_EDITX3, "x3"); <br />
	SetDlgItemText(IDC_EDITX4, "x4");<br />
	SetDlgItemText(IDC_EDITX5, "x5"); <br />
	SetDlgItemText(IDC_EDITY1, "y1");<br />
	SetDlgItemText(IDC_EDITY2, "y2"); <br />
	SetDlgItemText(IDC_EDITY3, "y3");<br />
<br />
	InvalidateRect(pictRect);<br />
}

Am I using the .Format correctly? The output on the screen is not correct. If Labels[1] is 10.26356897 then I get something like -85478 or something like that in the edit control when i run it. Could you give me an example of what it would take for my output to look like this: 10.3 I don't have a lot of space in the picture box so the output needs to be rounded to have only one number after the decimal place.

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra

Gary Kirkham13-Mar-03 9:03

13-Mar-03 9:03

student() wrote:
Would it then look like this?

Yes, however keep in mind that C arrays are 0 based...when you add a string to the CStringArray it will start at the 0 index. You can either handle it with the index or add a dummy string to the 0th location.

student() wrote:
Am I using the .Format correctly?

No, change the d to an f

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn13-Mar-03 9:13

13-Mar-03 9:13

Alright! That worked perfectly! I REALLY appreciate the help.

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra

Gary Kirkham13-Mar-03 9:08

13-Mar-03 9:08

Disregard the first part of my last post...I didn't see that you had used SetSize. Since the array is zero based, in order to start at an index of 1 then you will need to make the array size one larger than the number of items you are storing.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn13-Mar-03 11:06

13-Mar-03 11:06

One last question..

Why will this work...

strLabels[3].Format("%.2f\n", dblLabels[3]);

But this won't? WTF | :WTF:

for (int i = 1; i < 26; i++)<br />
     strLabels[i].Format("%.2f\n", dblLabels[i]);

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra

Gary Kirkham13-Mar-03 11:10

13-Mar-03 11:10

I don't see anything wrong with what you posted. What does it do?

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn13-Mar-03 11:19

13-Mar-03 11:19

The output on the screen shows -9255 for every string no matter what is in my dblLabels array when I use a for loop. If I put the literal index in it works but that would be too many lines of code.

Heres the whole thing again just in case:

void CGraphView::OnBnClickedBtnplot()<br />
{<br />
	GetDlgItem(IDC_PICT)->GetWindowRect(pictRect);<br />
	ScreenToClient(pictRect);<br />
<br />
	//Array of label strings<br />
	CStringArray strLabels;<br />
	strLabels.SetSize(26);<br />
<br />
	//Array of double labels [1-26] one for each has mark<br />
	//Don't use all of them though<br />
	double* dblLabels = GetLabelVals();<br />
<br />
	for (int i = 1; i < 26; i++)<br />
		strLabels[i].Format("%.2f\n", dblLabels[i]);<br />
<br />
	SetDlgItemText(IDC_EDITINTERSECT, "INT"); <br />
	SetDlgItemText(IDC_EDITY1, strLabels[3]);<br />
	SetDlgItemText(IDC_EDITY2, strLabels[6]); <br />
	SetDlgItemText(IDC_EDITY3, strLabels[9]);<br />
	SetDlgItemText(IDC_EDITX1, strLabels[12]); <br />
	SetDlgItemText(IDC_EDITX2, strLabels[15]); <br />
	SetDlgItemText(IDC_EDITX3, strLabels[18]); <br />
	SetDlgItemText(IDC_EDITX4, strLabels[21]);<br />
	SetDlgItemText(IDC_EDITX5, strLabels[24]); <br />
	<br />
	InvalidateRect(pictRect);<br />
}

Gary Kirkham13-Mar-03 11:40

13-Mar-03 11:40

Should work... Run it in debug mode and check each value set by this call

student() wrote:
double* dblLabels = GetLabelVals();

make sure each value in dblLabels is set properly.

I ran the following on my machine at it worked perfectly

CStringArray strLabels;
strLabels.SetSize(26);

double arr[] = { 0 , 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
                 11, 12, 13, 14, 15, 16, 17, 18, 18, 20,
                 21, 22, 23, 26, 25 };


for (int i = 1; i < 26; i++)
{
    strLabels[i].Format("%.2f\n", arr[i]);
    AfxMessageBox(strLabels[i]);
}

Other than that I don't know what to tell you

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn13-Mar-03 17:19

13-Mar-03 17:19

Gary...

Yeah something weird is going on. I ran it in the debugger and my dbl array is fine. The weird part is that after only one iteration of the for loop, all 26 of the values in the string array are set to -9255 plus about ten other numbers after that. I don't understand how one iteration could change all the values in the array.

Anyway..Thanks for your help..I really appreciate it.

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra

Gary Kirkham14-Mar-03 2:09

14-Mar-03 2:09

Just for kicks, try using the CStringArray GetAt and SetAt functions instead of the [] operator.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Gary Kirkham14-Mar-03 2:33

14-Mar-03 2:33

You can also us a vector. Here is an example

vector<CString> strLabels;
strLabels.reserve(26);
CString string;

strLabels.push_back("");  // this takes care of index 0

for (int i = 1; i < 26; i++)
{
    string.Format("%.2f\n", dblLabels[i]);
    strLabels.push_back(string);
}

put this at the top of you cpp file

#include <vector>
using std::vector;

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Gary Kirkham14-Mar-03 2:35

14-Mar-03 2:35

the first line of code sould look like this

vector<CString>strLabels;

I forgot the message software doesn't like the <> symbols

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Brent Lamborn15-Mar-03 10:37

15-Mar-03 10:37

Just thought I would let you know since you helped me so much...

I didn't even need to convert to strings. I add some code to my GetLabelVals function and changed the name of it to SetLabels(). I didn't realize it before but you can attach a double variable to the edit controls then, I just set the var attached to each box using the corresponding element in my double array. Then to have it appear on the screen -- I call UpdateData(false). I knew I could get the value in the box with an attached variable but I just figured out that I can set it using a variable also, using the UpdateData(false) call. So much work just for that!!

...Brent

"It has become appallingly obvious that our technology has exceeded our humanity."
- Albert Einstein (1879-1955)

"I think there is a world market for maybe five computers."
- Thomas Watson (1874-1956), Chairman of IBM, 1943

"640K ought to be enough for anybody."
- Bill Gates (1955-), in 1981

"Half this game is ninety percent mental."
- Yogi Berra