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What does IOStreams do that fopen etc doesn't?
Tim Smith
Descartes Systems Sciences, Inc.
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I'm not sure, but let me hazard some guesses.
IOStreams are C++ based, and a file stream will always close the file in it's destructor, even if an exception is raised, as soon is it goes out of scope.
IOStreams can be extended to allow one step reading/writing of custom file types, as well as custom modifiers that need only be written once and work with every type to be streamed.
Once the code is written, output can be streamed to any other stream type ( the console, a custom stream type, etc. ), simply by changing the type of the stream, all the other code will remain valid.
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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I just thought that since he's using MFC he might as well use CFile.
Sprudling
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I just thought that since he's using MFC he might as well use CFile.
Fair enough. I thought so long as he's reading a file he may as well learn the best way to do it. I was asking seriously, because I didn't know if there actually is some reason one might choose CFile beyond sticking with MFC.
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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Thanks for all the help. I knew it should not be that hard.
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Here would be the basics to read a file in C++:
#include < fstream.h >
void main()
{
//File Stream Object
fstream DataFile;
char FileName[81];
cout << "Enter the name of the file you wish to open\n";
cin.getline(FileName, 81);
DataFile.open(FileName, ios::out);
}
Nick Parker
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i don't understand why the insertitem function is good and the text doesn't appear!!
void CMyListView::OnInitialUpdate()
{
CListView::OnInitialUpdate();
ModifyStyle(0, LVS_REPORT,0);
// this code only works for a report-mode list view
//ASSERT(GetStyle() & LVS_REPORT);
// Gain a reference to the list control itself
CListCtrl& theCtrl = GetListCtrl();
// Insert a column. This override is the most convenient.
theCtrl.InsertColumn(0, _T("Names"), LVCFMT_CENTER);
// The other InsertColumn() override requires an initialized
// LVCOLUMN structure.
LVCOLUMN col;
col.mask = LVCF_FMT | LVCF_TEXT;
col.pszText = _T("Version");
col.fmt = LVCFMT_CENTER;
theCtrl.InsertColumn(1, &col);
theCtrl.InsertColumn(2,"Description",LVCFMT_CENTER);
// Set reasonable widths for our columns
theCtrl.SetColumnWidth(0, 200);
theCtrl.SetColumnWidth(1, 100);
theCtrl.SetColumnWidth(2, 100);
GetListCtrl().InsertItem(0, "First row");
}
GetListCtrl().InsertItem(0, "First row") is good but the text doesn't appear!!
Help me, please
PS: LVS_TYPEMASK == LVS_LIST only Michael Dunn. It is not that
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I use this code in my view class (according to Christian Graus articles about GDI+)
using namespace Gdiplus;
Graphics graphics(pDC->m_hDC);
Pen pen(Color(255,234,0,123));
int y = 0;
for (int x = 0; x <= 250; x += 30)
{
graphics.DrawLine(&pen, x, 0, 0, y);
graphics.DrawLine(&pen, x, 250, 250, y);
graphics.DrawLine(&pen, y, 0, 250, x);
graphics.DrawLine(&pen, y, 250, 0, x);
y += 30;
}
When I run the application nothing appear in client area,but after I minimiza and maximiza framework then I can see lines
Does anybody know the reason?
Thanks
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Where are you doing the drawing ?
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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View class,OnDraw()
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Mazdak wrote:
View class,OnDraw()
Well, that's correct. Put in a break point to see if it gets called on startup, because the fact that forcing WM_PAINT by minimise and maximising the window draws OK means the code is working fine.
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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I put breakpoint and somrthing wrong with this line:
Graphics graphics(pDC->m_hDC);
pDC->m_hDC -------->
- m_hDC 0x01010053 HDC__ *
unused CXX0030: Error: expression cannot be evaluated int
m_hDC can not evaluated
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Sometimes the debug window says that, but the variable is OK. Or was pDC NULL ?
Anyhow, try dereferencing pDC instead of refering to m_hDC, because operator HDC is defined for CDC.
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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Sorry for bothering you but would you please give me sample,I don't know how to do that?
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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No bother at all. pDC is a *pointer* to a CDC, which is why you use a -> instead of a . to access it's members. A class can define an operator for a type, so that if a class is passed into a function that is looking for a different type, that type is returned. For example, CPoint wraps a POINT, and also defines operator POINT, so the underlying POINT is returned to functions that require it.
This will only work if you have an object, not a pointer. The way to turn a pointer into an object is to put a * in front of it. For example, if you had a CPoint * called pPoint, you could do this:
CPoint pt = *pPoint;
In the same way, you can do this
Graphics graphics(*pDC);
instead of
Graphics graphics (pDC->m_hDC);
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
I just want to hit my haed to the wall.
Still the same porblem
AHHHHHHHHHHHHHHHHHHHHHHHHHHHH 
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Did you check in the debugger if pDC is a valid object, or if it is 0 ?
Christian
I have come to clean zee pooollll. - Michael Martin Dec 30, 2001
Picture the daffodil. And while you do that, I'll be over here going through your stuff.
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Yes.it's valid and it is not 0,
but as I said m_hDC,and m_hAttribDC of it cannot be evaluated
but they are not 0 too
I didn't change anything in my setting of project
except I add GDI+ support,how can pDC be 0?
oh,I only changed OnDraw(CDC */*pDC*/)to OnDraw(CDC *pDC)
Does it help?
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Is this in a Document/View application?
The reason is that OnDraw() is called after the user makes a change through the view (minimizing, maximizing, drawing, resizing). Only when those things have changed *through* the view will it be updated. Simply drawing with code in OnDraw will not be seen until the next WM_PAINT message is thrown which happens on minimizing, maximizing, drawing, resizing, etc..
Then when those conditions are met, the view calls the OnPaint() handler function in response to the WM_PAINT message then a device context is created of class CPaintDC which calls your OnDraw() function. What you can do is call RedrawWindow with the RDW_INTERNALPAINT flag(Which is kind of redundant on each WM_PAINT message) or call the InvalidateRect function which throws a WM_PAINT message (I think is better to do this) or do your application painting in OnPaint() using dc.m_hDC instead of pDC->m_hDC.
If I knew you were using a document class I might be of better help. Sounds to me like your not using a document class in your application. Hope that helps you. 
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Thanks for your information Jay,but after I move those code to OnPaint() again every things draw after I minimize or.. it.
And I don't know about another way you said
It is Document/View application,but I didn't use my doc class
thanks
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Sorry Mazy, looking through your code it should work as your wrote it. It should work in the OnDraw handler - I even tried your code and it compiled and the application worked well. The OnDraw handler seems to not be getting called on creation or not recieving the WM_PAINT message on creation. For reasons I don't understand.  Hopefully some one can help you.
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thanks Jay
Mazy
Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without
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Netmeisters,
I've had eVC 3.0 with the PPC SDK installed. I just
installed the PPC 2002 SDK (plus SSCE 1.1). Now when I
start up eVC, I have the choice of "Pocket PC" and "Pocket
PC 2002" platforms. Fine, but when I select the latter,
the only available targets are "Win32 (WCE ARM) Debug"
and "Win32 (WCE ARM) Release". "Win32 (WCE x86em)" does
not appear. An emulator starts up, but of course I get a
message stating that the executable doesn't match the
platform.
Thus I am unable to use the emulator for the PPC 2002 platform.
Since I don't know any other Pocket PC developers, I don't know what
the PPC 2002 SDK is *supposed* to look like. I assume this isn't what
it is supposed to do, but it is hard to see what I could have done
to screw it up, since there were no options during installation.
Your assistance much appreciated.
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AS far as I understand, teh String ARM processor is the only processor that is supported in 2002 and on.
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