C / C++ / MFC Discussion Boards

Re: Having issues with the cin.getline() function in C++

Member 147670009-Mar-20 11:01

9-Mar-20 11:01

I think I get what you are saying, but I just ran the program again and if I enter a valid weight (positive number) everything runs normally and at the end it displays the number I entered.

Re: Having issues with the cin.getline() function in C++

k50549-Mar-20 12:12

k5054

9-Mar-20 12:12

Sure, but if you do this

C++

if(weight != "\n")
{
  // ... 
  pigs[i].SetPigWeight(pigWeight);
}
else
    pigs[i].SetPigWeight(100.0); // Set default weight to 100.0
// ...

Now, when you hit enter, you would expect that the default weight would be used (i.e. set to 100.0), if the comparison is working as you expect. But it won't be, it will be set to zero. Believe me when I tell you that

C++

if (weight != "\n")

does not compare objects of type char* (ie c-style strings). You must use strcmp() to compare c-style strings. Better than using iostream::getline, take a look at std::getline. Your code might then look something like

C++

#include <string>
// ...
string input_string;
// ...
getline(cin, input_string);
if(input_string.length() != 0) // User entered a value
{
    // ...
}

Furthermore, what happens if you enter one hundred for the weight? It doesn't get set to 100, but zero, since atof("one hundred") == 0.0. A good solution should check that the input is a number. At the very least that the input string contains only the characters "0123456789.". Ideally you would check that there was only one decimal point, too.

Re: Having issues with the cin.getline() function in C++

Member 1476700010-Mar-20 8:49

Member 14767000

10-Mar-20 8:49

You're right, I copied and pasted that code to try it and it set the pig weight to the default of 0 instead of 100. I understand what you are saying now. Thank you so much for taking out the time to explain this to me in detail. This thing was really frustrating me and you really cleared it up for me, I really appreciate this!

Re: Having issues with the cin.getline() function in C++

k505410-Mar-20 9:04

k5054

10-Mar-20 9:04

You're very welcome.

String comparisons can be tricky in C/C++. I have over 30 years experience with C and it took me a couple of readings of your code to realize

C++

if(weight != "\n")

did not do what it looks like it should! I'm sure I'm not the only one who looked at that and didn't twig right away that the string comparisons were incorrect.

Re: Having issues with the cin.getline() function in C++

Stefan_Lang8-Mar-20 22:26

Stefan_Lang

8-Mar-20 22:26

k5054 already said it all.

But I'd like to add the general advice that you read up on the description of all I/O functions rather than making assumptions about what they return. Especially input functions.

Also, it is usually easier to read std::string objects rather than reading input of unknown length into limited size buffers. You can use the function getline(istream&, string) for that. See getline (string) - C++ Reference[^]

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

Re: Having issues with the cin.getline() function in C++

k50549-Mar-20 12:29

k5054

9-Mar-20 12:29

Stefan_Lang wrote:
Also, it is usually easier to read std::string objects rather than reading input of unknown length into limited size buffers. You can use the function getline(istream&, string) for

Additionally, you should expect your Teacher/TA/Assignment-marker to be an "evil knave of the worst kind", looking to find ways to make your program crash. For any input she/he might choose to cut/paste something like:

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

If you use std::getline(), rather than iostream::getline(), you should be able to handle any reasonable input sent your way.

Re: Having issues with the cin.getline() function in C++

Stefan_Lang9-Mar-20 21:41

Stefan_Lang

9-Mar-20 21:41

k5054 wrote:
Additionally, you should expect your Teacher/TA/Assignment-marker to be an "evil knave of the worst kind", looking to find ways to make your program crash

I've found I learned more from the 'evil knave' types than those who were 'playing nice'. Nothing prepares you better for the real world than nasty traps! Suspicious | :suss:

a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 12:56

Southmountain

8-Mar-20 12:56

I wrote a small utility tool with MFC (for user interface) and purely C++ code.
on Windows 10 and in Visual Studio 2017 IDE, I compiled this program into .exe file (i.e. HelloX.exe) in MFC dynamic DLL option.
So I put vcruntime140.dll and mfc140u.dll at the same folder.

I test my program on Windows Vista, it works well. I just tested this program on Windows XP and it did not work(few minutes ago).

Any suggestion or comments to share? thanks a million.

diligent hands rule....

modified 8-Mar-20 22:14pm.

Re: a not fun question: how to deploy a utility program written in MFC and C++

Jon McKee8-Mar-20 13:01

Jon McKee

8-Mar-20 13:01

C/C++/MFC forum or Quick Answers. Specific programming questions are generally frowned upon in the Lounge per the sticky post at the top.

Re: a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 16:06

Southmountain

8-Mar-20 16:06

thanks

diligent hands rule....

Re: a not fun question: how to deploy a utility program written in MFC and C++

Maximilien8-Mar-20 15:38

Maximilien

8-Mar-20 15:38

Deploy as in creating an installer ?

For small packages like yours, I would use inno setup to package your software.

I'd rather be phishing!

Re: a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 16:03

Southmountain

8-Mar-20 16:03

not using installer. just xcopy command etc.

diligent hands rule....

Re: a not fun question: how to deploy a utility program written in MFC and C++

Shao Voon Wong8-Mar-20 15:51

Shao Voon Wong

8-Mar-20 15:51

To deploy without having to install the VC++ dlls.

Linking to C runtime statically (Multithreaded (/MT) for Release build)
http://imageshack.com/a/img923/6600/ifeLcs.png

If you are using MFC, linking to MFC runtime statically.
http://imageshack.com/a/img921/1331/7eBoZW.png

The downside to linking statically is your executable size will be bigger but it only links the classes and functions your executable calls whereas, in the dynamically linkage case, the VC++ dlls have to contains all the code regardless your executable calls them or not.

Re: a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 16:04

Southmountain

8-Mar-20 16:04

I plan to use MFC DLL dynamically linked option. I have several utilities to distribute in one bundle...

diligent hands rule....

Re: a not fun question: how to deploy a utility program written in MFC and C++

Shao Voon Wong8-Mar-20 16:09

Shao Voon Wong

8-Mar-20 16:09

Then download VC++ redistributables to install on your client machine before running your utilities.

https://support.microsoft.com/en-sg/help/2977003/the-latest-supported-visual-c-downloads

Re: a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 16:24

Southmountain

8-Mar-20 16:24

thank you! first to know VS 2015, VS 2017,and VS2019 have the same redistribute.

diligent hands rule....

Re: a not fun question: how to deploy a utility program written in MFC and C++

Shao Voon Wong8-Mar-20 16:28

Shao Voon Wong

8-Mar-20 16:28

Yes, this is the future direction going forward because MS does not want the user to install many VC++ redistributables on their machine.

Re: a not fun question: how to deploy a utility program written in MFC and C++

Southmountain8-Mar-20 16:08

Southmountain

8-Mar-20 16:08

your screenshots are very helpful. thanks.

diligent hands rule....

Trying to add a menu bar to a dialog

ForNow29-Feb-20 16:07

ForNow

29-Feb-20 16:07

hi
I am trying to add a MENU bar to my Dialog when I look at this link seems I should be able to

DIALOG resource - Win32 apps | Microsoft Docs[^]

however after I add it

IDD_DIALOG21 DIALOGEX 0, 0, 790, 321
MENU IDR_MAINFRAME
STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU
CAPTION "Dialog"
FONT 8, "MS Shell Dlg", 400, 0, 0x1
BEGIN
    CONTROL         "",IDC_RICHEDIT21,"RichEdit20A",ES_MULTILINE | WS_BORDER | WS_TABSTOP,27,7,780,273
    LTEXT           "Static",IDC_STATIC15,7,7,20,273,WS_CLIPSIBLINGS
END

and open up the dialog in the resource editor it doesn't display
I tried creating a new project "Dialog Based" and the menu (control to add it ) in the wizard was grayed out

thanks

Re: Trying to add a menu bar to a dialog

Richard MacCutchan29-Feb-20 21:11

Richard MacCutchan

29-Feb-20 21:11

I don't have a VS version that includes the resource editor, so I have to do things manually. However, I can confirm that dialog boxes work fine with menus.

Re: Trying to add a menu bar to a dialog

ForNow1-Mar-20 11:55

ForNow

1-Mar-20 11:55

ok maybe it only display them when you do a SHowWindow

Re: Trying to add a menu bar to a dialog

Richard MacCutchan1-Mar-20 21:25

Richard MacCutchan

1-Mar-20 21:25

I thought you were talking about a modal dialog.

Re: Trying to add a menu bar to a dialog

leon de boer29-Feb-20 21:14

leon de boer

29-Feb-20 21:14

Easy to do it manually .. inside WM_INITDIALOG assuming the dialog window handle is hWnd

Try this

HMENU hMenubar;
HMENU hMenu;

hMenubar = CreateMenu();
hMenu = CreateMenu();

AppendMenuW(hMenu, MF_STRING, 10000, "&New");
AppendMenuW(hMenu, MF_STRING, 10001, "&Open");
AppendMenuW(hMenu, MF_SEPARATOR, 0, NULL);
AppendMenuW(hMenu, MF_STRING, WM_QUIT, "&Quit");

AppendMenuW(hMenubar, MF_POPUP, (UINT_PTR)hMenu, "&File");
SetMenu(hWnd, hMenubar);

In vino veritas

Re: Trying to add a menu bar to a dialog

ForNow1-Mar-20 11:55

ForNow

1-Mar-20 11:55

thanks

Re: Trying to add a menu bar to a dialog

Victor Nijegorodov1-Mar-20 20:54

Victor Nijegorodov

1-Mar-20 20:54

ForNow wrote:
after I add it
IDD_DIALOG21 DIALOGEX 0, 0, 790, 321
MENU IDR_MAINFRAME
...
END
and open up the dialog in the resource editor it doesn't display

Did you create the menu IDR_MAINFRAME itself?

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