C / C++ / MFC Discussion Boards

Christine Belisario25-Feb-22 20:48

25-Feb-22 20:48

#include<stdio.h>

int getFactorial(int);

int main(void) {
    int n;
    printf("Enter n: ");
    scanf("%d",&n);

    printf("Factorial of %d is %d", n, getFactorial(n));

    return 0;
}

int getFactorial(int n) {
    // how to Implement this recursive function 
}

Re: C

Richard MacCutchan25-Feb-22 22:52

Richard MacCutchan

25-Feb-22 22:52

Christine Belisario wrote:
// how to Implement this recursive function

Google will find you many explanations of the factorial function. You just need to think about how you could implement it in code.

Re: C

RedDk26-Feb-22 8:47

RedDk

26-Feb-22 8:47

When you've got a plank of code like this, and haven't necessarily begun stepping a mast of methods by leafing through your function library, presumeably squirreled away in the hold in a rat-free database, sometimes it's best to just go to a search engine that's got three sheets to the wind (open to the public), type in each word grain separated by commas and hammer the return.

And marking the returns using your favorites folder by hanging the list of code fragments off the hook of the internet browser you're buckling, for future reference, you're well on your way to driving the sea with your bark of ... lively functions ... and saving CP from a dumb trend which is hopefully on it's way south.

Re: C

Greg Utas26-Feb-22 10:32

Greg Utas

26-Feb-22 10:32

Prize winner for metaphor density. Big Grin | :-D

Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing.

how to dynamically delete sub-control created in run-time

wuxianzhong18-Feb-22 15:54

wuxianzhong

18-Feb-22 15:54

first of all, i shall thanks all of you guys.
In my project, i created some STATIC & EDIT controls in a CDialog and set these control's parent to a group box(also a STATIC control).
it works well for create, but it can't be delete dynamically.
For example, i create 5 EDIT control then delete it(there are no sub-controls in group box this time), and i create 2 EDIT control again, oops! there are 5 EDIT control showing in the group box. So, i guess this caused by the group box haven't refreshed in time. and then i sendmessage to group box to force it to refresh. unfortunately it doesn't works.
here is my code:
<pre lang="C++">
void CPLCDlg::DynamicCreateEdit(UINT nNums)
{
const int YSpace = 15;
const int EHeight = 20;
const UINT EDITID = 72000;
if (nNums <= 0)
return;
CButton* pGroup = (CButton*)GetDlgItem(IDC_STATIC_GROUP);
if (NULL != pGroup)
{
if (NULL != m_pDynEdit && m_siNumsOfDynEdit > 0)
{
for (short i = 0; i < m_siNumsOfDynEdit; i++)
{
if (NULL != m_pDynEdit[i].GetSafeHwnd())
{
m_pDynEdit[i].ShowWindow(SW_HIDE);
m_pDynEdit[i].DestroyWindow();
}
delete m_pDynEdit[i];
}
delete[] m_pDynEdit;
m_pDynEdit = NULL;
::SendMessage(pGroup->GetSafeHwnd(), WM_ERASEBKGND, 0, 0);
}
pGroup->Invalidate(FALSE);
pGroup->RedrawWindow();
pGroup->UpdateWindow();
CRect rcPos;
CString str;
rcPos.SetRectEmpty();
m_pDynEdit = new CEdit[nNums]();
for (short i = 0; i < nNums; i++)
{
rcPos.left = 10;
rcPos.top = 20 + (EHeight + YSpace) * i;
rcPos.right = rcPos.left + 30;
rcPos.bottom = rcPos.top + EHeight;
str.Empty();
str.Format(_T("%d"), i + 1);
if (m_pDynEdit[i].CreateEx(WS_EX_STATICEDGE, _T("EDIT"), (LPCTSTR)str, ES_CENTER | WS_VISIBLE | WS_CHILD | WS_TABSTOP, rcPos, pGroup, EDITID + i))
{
//m_pDynEdit[i].SetWindowText(_T("0"));
}

}
m_siNumsOfDynEdit = nNums;
}
}

</pre>

Re: how to dynamically delete sub-control created in run-time

Gerry Schmitz18-Feb-22 20:30

Gerry Schmitz

18-Feb-22 20:30

Just recreate the dialog? Place it over the old and delete the old, if it's noticeable. (25 cent solution)

"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I

Re: how to dynamically delete sub-control created in run-time

Victor Nijegorodov18-Feb-22 21:18

Victor Nijegorodov

18-Feb-22 21:18

Rather than destroy and recreate just hide and then show again them!
Do destroy/delete only by destroying the dialog itself!

Re: how to dynamically delete sub-control created in run-time

Randor 19-Feb-22 6:27

Randor

19-Feb-22 6:27

Looks like you send a WM_ERASEBKGND message to the parent group window (pGroup) and then redraw it. But parent windows will clip the child windows[^]. This is why you still see the windows you deleted.

In other words when you invalidate/redraw pGroup it skips over the rectangles where your m_pDynEdit child windows were being drawn.

You can use the ExcludeClipRect function[^] to remove the clipped rectangles from the clipping region.

Also, you can use the RectVisible function[^] to check for clipping.

I'm on a TV, I apologize in advance for any typos.

Azure DevOps Chocolatey question : install vs2022

Maximilien17-Feb-22 7:52

Maximilien

17-Feb-22 7:52

(I'm not sure there's a better place to ask)

I'm trying to use VS2022 in our build pipeline.

I have a pipeline like this :

Quote:
pool:
vmImage: 'windows-latest'

variables:
solution: 'MySolution.sln'

steps:

task: CmdLine@2
displayName: 'Choco install additional packages'
inputs:
script: |
choco install windows-sdk-8.1 visualstudio2017community microsoft-build-tools-2013 visualstudio2022professional
task: VSBuild@1
displayName: 'Build Debug143|x64'
inputs:
vsVersion: '17.0'
solution: '$(solution)'
maximumCpuCount: true
msbuildArchitecture: 'x64'
platform: 'x64'
configuration: 'Debug143'

I get errors that it cannot find the installation.

Quote:
2022-02-17T18:46:30.0197396Z ##[error]MyProject.vcxproj(77,3): Error MSB4019: The imported project "C:\Program Files\Microsoft Visual Studio\2022\Professional\MSBuild\Microsoft\VC\v170\Microsoft.Cpp.Default.props" was not found. Confirm that the expression in the Import declaration "C:\Program Files\Microsoft Visual Studio\2022\Professional\MSBuild\Microsoft\VC\v170\Microsoft.Cpp.Default.props" is correct, and that the file exists on disk.

When I put a "dir /s" in my pipeline, it looks like VS2022 is not installed in that path.

I'm not sure what I have to do to make it work.

Any Idea ?
Thanks.

CI/CD = Continuous Impediment/Continuous Despair

Re: Azure DevOps Chocolatey question : install vs2022

Mircea Neacsu17-Feb-22 8:02

Mircea Neacsu

17-Feb-22 8:02

Not sure if it applies to you but this is the magic incantation I use find latest VS installation:

BAT

@echo off
rem
rem Setup environment for MSBuild 2017 and later rem

if not "%VSCMD_VER%"=="" (
  echo MSBuild environment is already set
  goto :EOF
) 
rem VS2017U2 contains vswhere.exe if "%VSWHERE%"=="" set "VSWHERE=%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe"

for /f "usebackq tokens=*" %%i in (`"%VSWHERE%" -latest -products * -requires Microsoft.Component.MSBuild -property installationPath`) do (
  set VSInstallDir=%%i
)
rem echo Visual studio installation folder is: %VSInstallDir% rem "%VSInstallDir%\common7\tools\vsdevcmd.bat" "%VSInstallDir%\common7\tools\vsmsbuildcmd.bat"

Mircea

Re: Azure DevOps Chocolatey question : install vs2022

Maximilien18-Feb-22 3:23

Maximilien

18-Feb-22 3:23

Thanks I will look at it.
Thumbs Up | :thumbsup:

CI/CD = Continuous Impediment/Continuous Despair

Re: Azure DevOps Chocolatey question : install vs2022

Mircea Neacsu18-Feb-22 5:06

Mircea Neacsu

18-Feb-22 5:06

I just noticed the bad formatting. Sorry, it's from CP not me.

I tried editing my post but in the edit box the text shows OK. Not sure what's going on but smells like a bug.

Mircea

Message Closed

13-Feb-22 18:51

Member 14968771

13-Feb-22 18:51

Message Closed

modified 15-May-23 19:07pm.

Re: resource wanted - print control / color codes

Gerry Schmitz13-Feb-22 19:32

Gerry Schmitz

13-Feb-22 19:32

\u001B is an "escape" (27).

Re: resource wanted - print control / color codes

Richard MacCutchan13-Feb-22 22:24

Richard MacCutchan

13-Feb-22 22:24

Whatever code is producing that output, it is trying to set coloured text via the ANSI escape codes - Wikipedia[^].

Re: resource wanted - print control / color codes

Peter_in_278013-Feb-22 22:31

Peter_in_2780

13-Feb-22 22:31

They are ANSI escape codes for colors, etc. See, for example, ANSI Escape Codes · GitHub[^]

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Static OwnerDraw SS_OWNERDRAW DrawItem not being called

ForNow7-Feb-22 14:53

ForNow

7-Feb-22 14:53

I am going to paste all the relevant parts the resource control statements
I am not quite sure what drives the Drawitem at one point I thought it was SetWindowText (I do that to )
have a breakpoint at the DRAWITMEM and doesnt get called

thanks

IDD_DIALOG10 DIALOGEX 0, 0, 769, 429
STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_VISIBLE | WS_CAPTION | WS_SYSMENU
CAPTION "Storage View / Change"
FONT 8, "MS Shell Dlg", 400, 0, 0x1
BEGIN
    CONTROL          "",IDC_TCB,"Static",WS_CHILD| SS_OWNERDRAW, 45,30,47,8
    CONTROL           "Owning TCB",IDC_TCB_LABEL,"Static",WS_CHILD | SS_OWNERDRAW, 41,13,58,8
    CONTROL           "",IDC_SP,"Static",WS_CHILD | SS_OWNERDRAW ,164,28,43,8
    CONTROL           "Storage SubPool",IDC_SUBPOOL_LABEL,"Static", WS_CHILD | SS_OWNERDRAW, 162,12,55,8
    CONTROL           "",IDC_ASID,"Static", WS_CHILD | SS_OWNERDRAW, 265,26,32,8
    CONTROL           "Asid",IDC_ASID_LABEL,"Static", WS_CHILD | SS_OWNERDRAW ,269,9,31,8,SS_OWNERDRAW
    CONTROL           "",IDC_FP,"Static", WS_CHILD | SS_OWNERDRAW , 399,31,19,8
    CONTROL           "Fetch Protect Key",IDC_FP_LABEL,"Static",WS_CHILD | SS_OWNERDRAW ,392,15,63,8
    CONTROL         "",IDC_CUSTOM5,"PieCOntrol",WS_TABSTOP,617,99,109,109
    COMBOBOX        IDC_COMBO1,491,236,48,30,CBS_DROPDOWN | CBS_SORT | WS_VSCROLL | WS_TABSTOP
    CONTROL         "",IDC_EDIT2,"RichEdit20A",ES_MULTILINE | WS_BORDER | WS_TABSTOP,45,106,494,314
    COMBOBOX        IDC_COMBO2,637,244,67,16,CBS_DROPDOWN | CBS_SORT | WS_VSCROLL | WS_TABSTOP
    LISTBOX         IDC_LIST2,641,310,68,11,LBS_SORT | LBS_NOINTEGRALHEIGHT | WS_VSCROLL | WS_TABSTOP
    CONTROL           "Storage Area",IDC_AREA_LABEL,"Static", WS_CHILD | SS_OWNERDRAW , 534,14,58,8
    CONTROL           "",IDC_AREA,"Static", WS_CHILD | SS_OWNERDRAW , 537,25,31,8
    CONTROL           "Storage Key",IDC_KEY_LABEL,"Static", WS_CHILD | SS_OWNERDRAW, 651,17,48,8
    CONTROL           "",IDC_KEY,"Static", WS_CHILD | SS_OWNERDRAW , 654,31,30,8
END

Defined in the Dialog class

C++

CMystatic ctcb, csubpool, casid, cfp, carea, ckey, ctcblabel, csubpoolabel, casidlabel,cfplabel, carealabel, ckeylabel;

The CMystatic class

C++

#pragma once
#include "afx.h"
#include "afxwin.h"
class CMystatic : public CStatic
{

    DECLARE_DYNAMIC(CMystatic)
public:
    CMystatic();
   // void Dump();
    virtual void DrawItem(LPDRAWITEMSTRUCT pdi);
    BYTE red;
    BYTE green;
    BYTE blue;
    char fontface[16];
    int width;
    char text[9];
protected:
    DECLARE_MESSAGE_MAP()
    // private:
     //   CDumpContext dc;
};

The DDX statements

C++

void CStorge::DoDataExchange(CDataExchange* pDX)
{
	CDialogEx::DoDataExchange(pDX);
	
	DDX_Control(pDX, IDC_ASID_LABEL, casidlabel);
	DDX_Control(pDX, IDC_ASID, casid);
	DDX_Control(pDX, IDC_SUBPOOL_LABEL, csubpoolabel);
	DDX_Control(pDX, IDC_SP, csubpool);
	DDX_Control(pDX, IDC_TCB_LABEL, ctcblabel);
	DDX_Control(pDX, IDC_TCB, ctcb);
	DDX_Control(pDX, IDC_FP_LABEL, cfplabel);
	DDX_Control(pDX, IDC_FP, cfp);
	DDX_Control(pDX, IDC_AREA_LABEL, carealabel);
	DDX_Control(pDX, IDC_AREA, carea);
	DDX_Control(pDX, IDC_KEY_LABEL, ckeylabel);
	DDX_Control(pDX, IDC_KEY, ckey);
	DDX_Control(pDX, IDC_EDIT2, (CWnd&) *storagepointer);
			
}

The DRAWITEM

C++

IMPLEMENT_DYNAMIC(CMystatic, CStatic)

CMystatic::CMystatic()
{

}

void CMystatic::DrawItem(LPDRAWITEMSTRUCT pdi)
{
    ASSERT(pdi->CtlType == ODT_STATIC);
    CDC* pDC = CDC::FromHandle(pdi->hDC);
    ASSERT(pDC != NULL);
    CWnd* phwnd = CWnd::FromHandle(pdi->hwndItem);
    strcpy_s(&fontface[0],15, "Times New Roman");
    pDC->FillSolidRect(&pdi->rcItem, RGB(240, 255, 255));

    CString str;
    phwnd->GetWindowText(str);
   
        // Get text format options.
        UINT nFormat = DT_CENTER;
        // get actual settings in case they has been changed
        DWORD dwStyle = phwnd->GetStyle();
        // Don't process '&' prefix sequences
        if (dwStyle & SS_NOPREFIX)
            nFormat |= DT_NOPREFIX;
        // vertically centered text and no new line
        if ((dwStyle & SS_CENTERIMAGE) && str.Find(_T('\n')) < 0)
        {
            nFormat &= ~DT_WORDBREAK;
            nFormat |= DT_VCENTER | DT_SINGLELINE;	// must set both!
        }
        if (dwStyle & SS_ELLIPSISMASK)
        {
            nFormat &= ~DT_EXPANDTABS; // not supported with ellipsis
            switch (dwStyle & SS_ELLIPSISMASK)
            {
            case SS_ENDELLIPSIS:
                nFormat |= DT_END_ELLIPSIS | DT_MODIFYSTRING; break;
            case SS_PATHELLIPSIS:
                nFormat |= DT_PATH_ELLIPSIS | DT_MODIFYSTRING; break;
            case SS_WORDELLIPSIS:
                nFormat |= DT_WORD_ELLIPSIS; break;
            }
        }
        // The complete background has just been filled.
        // So use transparent mode for faster text drawing.
        // Saving and restoring of colors and mode is not necessary (drawing only performed here).
     if (!str.IsEmpty())
     {
        pDC->SetBkMode(TRANSPARENT);
        pDC->SetTextColor(RGB(0,0,255));

        int mapmode = pDC->GetMapMode();
        CFont l_font;
        LOGFONT lf;
        TEXTMETRIC tm;
        memset(&lf, 0x00, sizeof(lf));

        pDC->GetTextMetrics(&tm);

        lf.lfHeight = tm.tmHeight + 4;

        CSize sz;
        sz = pDC->GetTextExtent(str, str.GetLength());
        lf.lfWidth = (sz.cx / str.GetLength()) + width;
        lf.lfWeight = 700;
        strcpy_s(lf.lfFaceName,15, &fontface[0]); // Need a face name "Arial".
        l_font.CreateFontIndirect(&lf);
        pDC->SelectObject(&l_font);
        // The text string may be modified if DT_MODIFYSTRING is set!
        LPTSTR lpszText = str.GetBuffer();

        pDC->DrawText(lpszText, -1, &pdi->rcItem, nFormat);

        str.ReleaseBuffer();



    }
    else
    {
        pDC->SetTextColor(RGB(255, 0, 0));
        pDC->DrawText(&text[0], -1, &pdi->rcItem, nFormat);

    }
}

BEGIN_MESSAGE_MAP(CMystatic, CStatic)
END_MESSAGE_MAP()

Re: Static OwnerDraw SS_OWNERDRAW DrawItem not being called

Richard MacCutchan7-Feb-22 21:08

Richard MacCutchan

7-Feb-22 21:08

The WM_DRAWITEM message gets sent to the parent window when the control needs to be drawn. So you need to handle that message in your dialog's message handler. See WM_DRAWITEM message (Winuser.h) - Win32 apps | Microsoft Docs[^] for more details. The DRAWITEMSTRUCT (winuser.h) - Win32 apps | Microsoft Docs[^] contains details and flags which identify which phase of drawing needs to be performed. It is rather convoluted but I have used it in the past and it does work, as long as you follow the rules.

modified 8-Feb-22 5:39am.

Re: Static OwnerDraw SS_OWNERDRAW DrawItem not being called

Victor Nijegorodov7-Feb-22 22:49

Victor Nijegorodov

7-Feb-22 22:49

No Richard. The OP tries to use/override the virtual method of the MFC CStatic class: CStatic Class | Microsoft Docs
I have no idea why he has any problem here. I tried his DrawItem implementation and it works (however, I had to fix some bugs in his sample)

Re: Static OwnerDraw SS_OWNERDRAW DrawItem not being called

Richard MacCutchan7-Feb-22 23:39

Richard MacCutchan

7-Feb-22 23:39

Thanks, it's too many years since I used MFC.

Re: Static OwnerDraw SS_OWNERDRAW DrawItem not being called

Victor Nijegorodov7-Feb-22 22:42

Victor Nijegorodov

7-Feb-22 22:42

I added an owner draw static to my MFC dialog application, added your code for DrawItem, fixed some bugs in your CMyStatic class, and I have to say: it works.

Re: Static OwnerDraw SS_OWNERDRAW DrawItem not being called

ForNow8-Feb-22 1:23

ForNow

8-Feb-22 1:23

Thank you let me re-visit

Re: It gets called at the end of the OnInitDialog

ForNow8-Feb-22 11:25

ForNow

8-Feb-22 11:25

Hi
When posted I was under the impression that Drawitem runs after window Creation which in my case is the DDX_Control however it runs after the return of the OnInitDialog

Sorry and thanks

ways to write code for a class

Calin Negru6-Feb-22 7:43

Calin Negru

6-Feb-22 7:43

This subject is a foggy topic in my head could you help me clarify things a little.
basically there are two ways to write a class in c++
-declare a class and add in the class body only class member variables and function declarations and then layout the code for function bodies somewhere outside (in the same cpp file or in a different cpp file if the class declaration was made in a header file)
-declare a class and add in the class body class member variables and function bodies (not just the declarations), the later solution resembling how things are done in C#. The former approach can be used in the main cpp file but also in a c++ header file. The later approach can only be used in the main cpp file is that correct? could you place for instance a class declaration containing function bodies (not just declarations) in a another cpp file belonging to the same project or in a header file?
Is it that the h and cpp file of the same name are compiled into a single binary file which is then used by the binary form of the main cpp file? and that the header file is there just as an index/entry point to the class functions

Re: ways to write code for a class

Mircea Neacsu6-Feb-22 9:15

Mircea Neacsu

6-Feb-22 9:15

Let's talk first about C where the C++ came from. From the compiler's point of view there is not difference between .h and .cpp files. They are both source files and it treats them identically. By convention (and only by convention) we place declarations in the .h file and code in .cpp one. Also we have to make sure that the compiler sees the code generating lines only once. For instance if you place a function definition:

C++

int my_function () {return 3;}

in a .h file and that file is included by two different .cpp files, the compiler will happily compile them but the linker will complain that it has two instances of the same function and it doesn't know which one to pick.

What we do in this case is to place a function declaration in the .h file:

C++

int my_func ();

Now we can put the function definition in one of the .cpp files and everyone will be happy: the compiler has a declaration for the function so it can check all calls against the function prototype and the linker has only one body for the function.

Now we move to C++. Assume you place this:

C++

class A {
public:
  int func1 ();
  int func2 () {return 2;}
};

in a header file. The member func1 is only declared while the member func2 is also defined. Here the compiler performs a little trick: because the definition of func1 is within the body of a class it tells the linker to use only one instance of the generated code.

If we add a definition for func1 inside the same header file:

C++

class A {
public:
  int func1 ();
  int func2 () {return 2;}
};

int A::func1 () {return 1;}

the compiler will treat it as a regular function and again, if the header is included by two different .cpp file, the linker will complain that the function is doubly defined.

We can do two things now. One is to place an inline specifier in front of the function:

C++

class A {
public:
  int func1 ();
  int func2 () {return 2;}
};

inline int A::func1 () {return 1;}

The compiler will use the same trick as if the function would have been defined inside the body of the class and tell linker to use only one instance.

The other is to simply place the function definition in a .cpp file and in that case the linker will see it only once.

So in the end you have 3 alternatives:
1. place the function definition in the class body.
2. place it in the header file and make it inline.
3. place it in one .cpp file

Which solution you choose depends on your teste and what you want to achieve. The difference between 1 and 2 is purely a question of style (I prefer 2, but that's just me). Number 3 used to be by far the most popular choice until recently when header only libraries have proliferated. It's up to you to decide.

Mircea

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