C / C++ / MFC Discussion Boards

anasshad3-Jul-13 2:11

3-Jul-13 2:11

Hello!!! I'm learning C language and trying to make a calculator. Here's the code:

#include <stdio.h>
int main()
{
    int a, b, add, sub, mul;
    float div;
    char choice='y';
    do {
    printf("Enter any choice:\n1. Addition(a)\n2. Subtraction(b)\n3. Multiplication(c)\n4. Division(d)\n5. Exit(x)");
    scanf("%c", &choice);
    switch(choice)
    {
                  case 'a':
                       {printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       add = a + b;
                       printf("Sum: %d\n", add);
                       break;}
                  case 'b':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       sub = a - b;
                       printf("Difference: %d\n", sub);
                       break;
                  case 'c':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       mul = a * b;
                       printf("Product: %d\n", mul);
                       break;
                  case 'd':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       div = a / b;
                       printf("Quotient: %f\n", div);
                       break;
                  case 'x':
                       break;
                       }
                       }while(choice!='x');

                  return 0;
                       }

The problem is that it is not looking very good. I'll be very thankful if anyone could help.

Re: Calculator in C Language

Richard MacCutchan3-Jul-13 2:42

Richard MacCutchan

3-Jul-13 2:42

anasshad wrote:
I'll be very thankful if anyone could help.

I would suggest spending some time looking through the beginners section articles[^] for ideas and examples.

Use the best guess

Re: Calculator in C Language

Maximilien3-Jul-13 2:45

Maximilien

3-Jul-13 2:45

Does it compile ?
Does it crash ?
Does it give wrong answer ?
Are you able to read numbers from the user ? (outside of this example?)
Have you tried debugging ?

Nihil obstat

Re: Calculator in C Language

Jonathan Davies3-Jul-13 3:03

Jonathan Davies

3-Jul-13 3:03

For a calculator the probable way to have it look would be like the keypad on a calculator, but as you're just starting that's a bit of a jump. As a first step why not try a Window or Dialog with two Edit boxes for the numbers and buttons to select +, - etc. The articles here will help with that as already mentioned.

Re: Calculator in C Language

David Crow3-Jul-13 4:47

David Crow

3-Jul-13 4:47

anasshad wrote:

The problem is that it is not looking very good.

Meaning what exactly? Confused | :confused:

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

Slider not working properly.?

mbatra312-Jul-13 23:52

mbatra31

2-Jul-13 23:52

Hi,

I have a slider control on a dialog box. I am playing a video file and slider moves according to the video elapsed. Suppose I have set the slider range to 100. Now till some point say 90, the slider moves to the point wherever I click the mouse. but at the last point in between some range say 90 - 100 (to the end of the slider), if I click the mouse button anywhere, slider jumps to the end.

I am using a TimeLine control where user can add more than 1 video (1, 2, 4, 8, 10 , 50 etc......), If I use only one video, slider moves as per the video progression.....Issue arises when I add more than 1 video and click on the start button, slider starts moving....Now when I drag the slider to any position or I click the mouse button anywhere on the slider control, slider thumb moves to that position and immediately jumps back to some other position. This is the Issue, I am facing.

Can anybody share some sample code where slider is moving with the video showing the progress of the video.

I want to implement a functionality similar to VLC player. Wherever user clicks the mouse, slider moves to that point.

Any help will be appreciated.

Regards,
Mbatra

modified 3-Jul-13 9:15am.

Re: Slider not working properly.?

Maximilien3-Jul-13 3:01

Maximilien

3-Jul-13 3:01

Derive you own class from CSliderCtrl and handle the left button down

(I have no merit, this is from a simple google search)

C++

void MySlider::OnLButtonDown(UINT   nFlags, CPoint   point)
{
    CSliderCtrl::OnLButtonDown(nFlags, point);
    CRect rectClient, rectChannel;
    GetClientRect(rectClient);
    GetChannelRect(rectChannel);
    int nPos = (GetRangeMax() - GetRangeMin())*(point.x - rectClient.left - rectChannel.left) / (rectChannel.right - rectChannel.left);
    SetPos(nPos);
}

Nihil obstat

Re: Slider not working properly.?

mbatra313-Jul-13 3:16

mbatra31

3-Jul-13 3:16

I have done this...its working ....

Please read below:

Hi,

I have a slider control on a dialog box. I am playing a video file and slider moves according to the video elapsed. Suppose I have set the slider range to 100. Now till some point say 90, the slider moves to the point wherever I click the mouse. but at the last point in between some range say 90 - 100 (to the end of the slider), if I click the mouse button anywhere, slider jumps to the end.

I am using a TimeLine control where user can add more than 1 video (1, 2, 4, 8, 10 , 50 etc......), If I use only one video, slider moves as per the video progression.....Issue arises when I add more than 1 video and click on the start button, slider starts moving....Now when I drag the slider to any position or I click the mouse button anywhere on the slider control, slider thumb moves to that position and immediately jumps back to some other position. This is the Issue, I am facing.

Can anybody share some sample code where slider is moving with the video showing the progress of the video.

I want to implement a functionality similar to VLC player. Wherever user clicks the mouse, slider moves to that point.

Any help will be appreciated.

Regards,
Mbatra

How I get the Header HDC of listview in custom draw?

JoneLe862-Jul-13 9:04

JoneLe86

2-Jul-13 9:04

I want to customize the header of a listview, so in NM_CUSTOMDARW i have

C++

Test = (LPNMLVCCUSTOMDARW)Lp <<lparam
(Test->nmcd.hdc)

which for the listview without the header, i tried using

C++

Test = (LPNMCUSTOMDARW)Lp <<lparam

and then

C++

Test->hdr.hwndFrom

C++

if(Test->hdr.hwndFrom == listview_getheader(LIST))

but it does not work, the listview_getheader(LIST) gives the right hwnd, but how about Test->hdr.hwndFrom, it seems i missed something...

Re: How I get the Header HDC of listview in custom draw?

Richard MacCutchan2-Jul-13 20:41

Richard MacCutchan

2-Jul-13 20:41

JoneLe86 wrote:
C++
Test = (LPNMCUSTOMDARW)Lp <<lparam

What is Test and what is its value, and that of lp, after this statement?

Use the best guess

Re: How I get the Header HDC of listview in custom draw?

JoneLe863-Jul-13 5:41

JoneLe86

3-Jul-13 5:41

LPNMCUSTOMDARW Test = (LPNMCUSTOMDARW)lp

I was in the wrong way, Jochen Arndt explained that I should subclass the header first...

Thanks

Re: How I get the Header HDC of listview in custom draw?

Jochen Arndt2-Jul-13 21:11

Jochen Arndt

2-Jul-13 21:11

The header control is a child window of a list. If you want to customize the header, you must use owner drawing for the header itself.

When using MFC, derive a CHeaderCtrl class and implement the virtual DrawItem() handler. To connect this header control class to your list, use subclassing. To enable owner drawing of header items, set the HDF_OWNERDRAW flag for the header items.

See Deriving a Custom CHeaderCtrl in the Using the Header Control[^] article.

This example contains complete implementation code including the DrawItem() function: http://www.codeguru.com/cpp/controls/listview/sorting/article.php/c977/Indicating-sort-order-in-header-control.htm[^].

Re: How I get the Header HDC of listview in custom draw?

JoneLe863-Jul-13 5:38

JoneLe86

3-Jul-13 5:38

hmm I wonder why Everything need to be subclassed, thanks for this information it did help....

AVI Splitter Filter does not return its mediatype

sdancer752-Jul-13 8:29

sdancer75

2-Jul-13 8:29

The AviSplitter Filter's input pin, according to the MSDN is accepting the following mediatype

MEDIATYPE_Stream, <br />
MEDIASUBTYPE_Avi

While my own async filter is trying to connect with this filter in the method (located in amfilter.cpp file)

C++

HRESULT CBasePin::TryMediaTypes(IPin *pReceivePin, __in_opt const CMediaType *pmt, IEnumMediaTypes *pEnum)

at the following statement that it supposed to receive the AVISplitter input pin, mediatype,

C++

hr = pEnum->Next(1, (AM_MEDIA_TYPE**)&pMediaType,&ulMediaCount);

it retuns FALSE.

Why is that happens ?

sdancer75

Re: AVI Splitter Filter does not return its mediatype

Richard MacCutchan2-Jul-13 20:37

Richard MacCutchan

2-Jul-13 20:37

sdancer75 wrote:
t retuns FALSE.

Why is that happens ?

Explanation is at http://msdn.microsoft.com/en-us/library/windows/desktop/dd376602(v=vs.85).aspx[^].

Use the best guess

Re: AVI Splitter Filter does not return its mediatype

sdancer752-Jul-13 22:01

sdancer75

2-Jul-13 22:01

Thanks,

It seems that AVISplitter does not suggest any mediatype but my mediatype fails at

C++

hr = pReceivePin->ReceiveConnection((IPin *)this, pmt);

with error code 0x8004022f

Do you have any idea ?

Regards,

sdancer75

Re: AVI Splitter Filter does not return its mediatype

Richard MacCutchan2-Jul-13 22:10

Richard MacCutchan

2-Jul-13 22:10

And what does that error code tell you?

Use the best guess

Re: AVI Splitter Filter does not return its mediatype

sdancer752-Jul-13 23:58

sdancer75

2-Jul-13 23:58

Debugging the dshow library, the first error internal decription is

0x8004022f error code<br />
VFW_E_INVALID_FILE_FORMAT

but the same dshow method returns to the caller, the following description

VFW_E_NO_ACCEPTABLE_TYPES<br />
0x8004022f

I think that something wrong is going on with my code in my async filter.

C++

HRESULT result = m_pIo->SyncRead(llPosition, lLength, pBuffer);

It reads the first 0x18 bytes and after that, it returns the error. Other tests I did, it continues to read or parsing the avi file, but my code fails.

If its not a read error, then something wrong went with the AVI header parse or the MediaType templates declaration.

Note that the AVI is fine and is tested successfuly with other 3rd party players.

Regards,

sdancer75

Re: AVI Splitter Filter does not return its mediatype

sdancer753-Jul-13 2:11

sdancer75

3-Jul-13 2:11

Ok Solved.

My mistake was a command in the

C++

CAsyncFilter::Load(LPCOLESTR lpwszFileName, const AM_MEDIA_TYPE *pmt)

function that is changing the absolute offset inside the file !!! I added that, for debugging purposes and I forgot to delete it when I reloaded the project a few days later.

So it was a read error !

Thank you.

PS : I was looking for that error one month now ! Oh God !!!

sdancer75

Process Failure at startup

ForNow2-Jul-13 6:38

ForNow

2-Jul-13 6:38

I have a process that some how fail at Initialization

it is a MFC C++ app so I inserted a __debugbreak at the first possible instance

which would be CWinAPP constructer the code starts but never seems to reach that point

(probably something to do with the build)

When I run this app from task manager I see it start and then it disappears

The Program when Initialized display a Main Window

I originally started this program using CreateProcess I get a return code 1 inidicating sucesss

but like I said it dies at initialization

When I run this program using "Start Debugging" from the Visual Studio IDE it seems to performs

properly

I am thinking That I use CreatePrcess with the DEBUG_PROCESS flag to get a better handle on

The problem

I appreciate any help

Thank you

Re: Process Failure at startup

Santhosh G_2-Jul-13 7:24

Santhosh G_

2-Jul-13 7:24

Try to log the startup sequence by some log mechanism, like OuputDebugString() or File write.
Is there any chance to have code which will run in Release mode?
Any code which is written by compiler directive like #ifndef.

C++

#ifndef _DEBUG
    ..
#endif

The following link may help you to find out this issue.
http://forums.codeguru.com/showthread.php?269905-Visual-C-Debugging-Why-does-program-work-in-debug-mode-but-fail-in-release-mode

In the debug build, if you have incorrect message handler signatures this doesnt cause any problems.

But MFC does a couple of naughty type casts in the message map macros. So when you build the same code in release mode, you are guranteed to run into trouble.

Re: Process Failure at startup

ForNow2-Jul-13 8:42

ForNow

2-Jul-13 8:42

Let me clarify I run the VC debugger from
The release mode code along with the .pdb I am able to see what's going on

Re: Process Failure at startup

Santhosh G_2-Jul-13 16:21

Santhosh G_

2-Jul-13 16:21

Yes it is possible to debug in release mode.
Details are given in the following link.

If an application works in a debug build, but fails in a release build, one of the compiler optimizations may be exposing a defect in the source code. To isolate the problem, disable selected optimizations for each source code file until you locate the file and the optimization that is causing the problem. (To expedite the process, you can divide the files into two groups, disable optimization on one group, and when you find a problem in a group, continue dividing until you isolate the problem file.)

http://msdn.microsoft.com/en-us/library/fsk896zz.aspx

Re: Process Failure at startup

ForNow2-Jul-13 17:59

ForNow

2-Jul-13 17:59

Somewhere between the initlization and the CWinApp constructer the code
dies

I think using DEBUG_PROCESS flags will send events at everypoint till
the process is created

Where does the m_pMainWnd delete?

yu-jian2-Jul-13 5:54

yu-jian

2-Jul-13 5:54

I have a client system, to create a CMainFrame object, but I am afraid that there will be memory leak about CMainFrame object.After step in, I cannot find where the m_pMainWnd pointer is deleted. Will I delete this pointer in the function
ExitInstance()? Big Grin | :-D

C++

BOOL CApp::InitInstance()
{
	CMainFrame* pMainFrame = new CMainFrame();
	if (!pMainFrame)  return FALSE;
	pMainFrame->LoadFrame(IDR_MAINFRAME,
		WS_OVERLAPPEDWINDOW | FWS_ADDTOTITLE, NULL,
		NULL);
	m_pMainWnd = pMainFrame;
	m_pMainWnd->UpdateWindow();
	return TRUE;
}

int CApp::ExitInstance()
{
	return CWinApp::ExitInstance();
}

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