C / C++ / MFC

ToolBar Combo - Changing Text After Selection?

9-Oct-08 22:43

LilKoopa wrote:
Write a program that uses a two-dimensional array of characters to hold the five student names, a single-dimensional array of five characters to hold the five students’ letter grade, and five singe-dimensional arrays of four doubles to hold each student’s set of test scores.

That is really very basic stuff. Try to write some code and post a question whenever you meet the first obstacle.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Help with Arrays

David Crow10-Oct-08 4:32

David Crow

10-Oct-08 4:32

LilKoopa wrote:
Create a New Project called YourLastnameGradeBook.

Have you done this?

LilKoopa wrote:
Write a program that uses a two-dimensional array of characters to hold the five student names

This approach is potentialy unsafe and not necessary with C++. For example:

vector<string> names;
string name;
 
for (int x = 0; x < 5; x++)
{
    cout << "Enter name #" << x + 1 << ": ";
    cin >> name;
 
    names.push_back(name);
}

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

Kyudos9-Oct-08 11:59

Kyudos

9-Oct-08 11:59

This is a niggling little cosmetic issue that I thought would be easy to solve with a bit of message manipulation. It is turning out to be unreasonably difficult.

I have a combobox on a toolbar (as part of the Objective Studio framework) and I have filled it with a fixed set of 'menu like' contents (it actually echos a dynamic menu in the app).

a la...

Title 1
  - Entry 11
  - Entry 12
  - Entry 13
Title 2
  - Entry 21
  - Entry 22

What I wanted to do, when an Entry is selected, was to automatically remove the ' - ' at the start of the string.

So I used the CBS_DROPDOWN style (instead of the CBS_DROPDOWNLIST) so I could 'edit' the contents of the selection, while using PreTranslateMessage to prevent keyboard edits. I then caught the CBN_SELCHANGE event, from which I can get the current selection, edit the text and then SetWindowText. This all works, but occurs BEFORE the combo box edit control updates, meaning the Entry is set back to list value (with the ' - '). I need a CBN event after update, but their isn't one.

Any suggestions? I don't really want to go so far as deriving a new control to solve this minor issue, but it is bugging me a bit.

Re: ToolBar Combo - Changing Text After Selection?

Kyudos12-Oct-08 14:17

Kyudos

12-Oct-08 14:17

OK...I solved this with what seems like an ugly hack, surely there must be a better way....

Anyways, what I did was to PostMessage a user message from the CBN_SELCHANGE event and strip the prefix in my user message handler, I just hope the messages continue to arrive in the correct order...

RTL_USER_PROCESS_PARAMETERS.CommandLine is only for current process?

Jack Rong9-Oct-08 9:53

Jack Rong

9-Oct-08 9:53

I used NtQueryInformationProcess to get
PROCESS_BASIC_INFORMATION and PEB and then RTL_USER_PROCESS_PARAMETERS.
But CommandLine of RTL_USER_PROCESS_PARAMETERS is always associated with the currect process although I passed in different PID into NtQueryInformationProcess() call.

By the way, I am using XP64.

Can you help.

Thanks

Jack Rong

Re: RTL_USER_PROCESS_PARAMETERS.CommandLine is only for current process?

CPallini9-Oct-08 10:00

Re: RTL_USER_PROCESS_PARAMETERS.CommandLine is only for current process?

9-Oct-08 10:00

Have you read the following notice in documentation [^]:

[NtQueryInformationProcess may be altered or unavailable in future versions of Windows. Applications should use the alternate functions listed in this topic.]

?

Jack Rong wrote:
although I passed in different PID into NtQueryInformationProcess() call.

You should pass the process handle, shouldn't you?
Smile | :)

Jack Rong9-Oct-08 10:33

Jack Rong

9-Oct-08 10:33

Thanks for your response.

Yes, I do pass the process handle, here is the example,

hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ,
FALSE, mypid );
NtQueryInformationProcess (hProcess, ProcessBasicInformation,
&pbi, sizeof(pbi), &dwSize);

Where "mypid" is what I want and is not current PID. But the CommandLine I got is the Current Process's CommandLine. So strange!

Yes, I realize that. But I am not sure which new function can be used in order to replace the "NtQueryInformationProcess()" though.

Jack

Re: RTL_USER_PROCESS_PARAMETERS.CommandLine is only for current process?

CPallini9-Oct-08 22:37

resource leak in destructor?

9-Oct-08 22:37

How do you get the command line? I don't see such a option in the documentation.
Smile | :)

George_George9-Oct-08 3:27

9-Oct-08 3:27

Hello everyone,

I understand there should be no exception thrown from destructor. But exception will block the remaining code to be executed until catch block.

In my destructor, I free resources step by step. But at some first step, there may be exception in destructor, so I suspect the remaining resources can not be freed correctly. In my class, I use member variable to hold resources.

My questions are,

- My current solution is to declare each member as smart pointer, so that to ensure the destructor will be called.

- I am not sure whether my concern is correct or no such issue -- e.g. member's destructor will always be called or not, even if I do not wrap them with auto_ptr?

thanks in advance,
George

CPallini9-Oct-08 3:42

9-Oct-08 3:42

George_George wrote:
e.g. member's destructor will always be called or not, even if I do not wrap them with auto_ptr

of course no destructor is called for objects allocated dynamically and assigned to standard (even if class member) pointers.
Smile | :)

George_George9-Oct-08 18:07

9-Oct-08 18:07

Thanks CPallini,

One more question, if the class member has destructor, even if

- we do not call it exeplicitly in the whole class's destructor;
- or because of exception execution flow, it is not executed

its destructor will be called when the current object instance destructs?

regards,
George

CPallini9-Oct-08 21:50

9-Oct-08 21:50

See here [^].
Smile | :)

George_George9-Oct-08 22:18

9-Oct-08 22:18

Thanks CPallini!

I think here is the answer,

--------------------
In reverse order of construction: First constructed, last destructed.

In the following example, b's destructor will be executed first, then a's destructor:

void userCode()
{
Fred a;
Fred b;
...
}
--------------------

So, I think the answer to my question whether destructor of member variable will be called in the following two situations is -- yes, they must be called. Correct understanding? Smile | :)

- we do not call it exeplicitly in the whole class's destructor;
- or because of exception execution flow, it is not executed.

regards,
George

CPallini10-Oct-08 0:17

10-Oct-08 0:17

The destructors of member variables are always implicit called, so you have NOT to call them explicitely.
Smile | :)

George_George10-Oct-08 0:33

10-Oct-08 0:33

Thanks CPallini!

From your reply, I think in the two situations, as long as I implement the destructor of the members properly, they will be called finally without any issues. Correct?

- we do not call it exeplicitly in the whole class's destructor;
- or because of exception execution flow, it is not executed.

regards,
George

led mike9-Oct-08 4:26

led mike

9-Oct-08 4:26

George_George wrote:
I am not sure whether my concern is correct or no such issue -- e.g. member's destructor will always be called or not, even if I do not wrap them with auto_ptr?

You are kidding right? With all the esoteric question you ask around here when you don't even know how destructors work. That is exactly why in the past I suggested you stop investigating some of the issues you were on about. You need to stick to fundamentals until you get a firm grasp of them. Until then you are basically lost.

Ah yes, just below is yet another good example:

George_George wrote:
For the following code, on x86 build, the output is

000000C8
000000C8

and on x64 build, the output is

CCCCCCCC000000C8
00000000000000C8

You are looking at and questioning what the compiler generates when you don't even know how destructors work. That makes no sense at all. It's even worse for someone that is constantly claiming they are trying to make sense of things. Unsure | :~

led mike

Mark Salsbery9-Oct-08 5:21

Mark Salsbery

9-Oct-08 5:21

You're still answering the bot, huh?

The history of "his" question topics is amazingly diverse,
sometimes just seemingly random.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Roger Stoltz9-Oct-08 5:30

Roger Stoltz

9-Oct-08 5:30

Couldn't agree more Mark.

Mark Salsbery wrote:
The history of "his" question topics is amazingly diverse,
sometimes just seemingly random.

In my opinion it usually begins with a seemingly basic question about a small detail, but when the answer comes it blows up to something else where George clearly has not grasped the concept and he refers to another detail in some obscure MSDN article or similar. From that point on it takes a good book to explain to George how it really works. This means that I've stopped answering until his questions shows that he has actually paid some attention and learnt something.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

led mike9-Oct-08 5:32

led mike

9-Oct-08 5:32

Mark Salsbery wrote:
sometimes just seemingly random.

Most of the time. He's just lost, but he sure maintains a great attitude with all the stuff hurled at him. It's hard to imagine that we will ever figure out what his deal is. He is the internet developer forum enigma. Smile | :)

led mike

George_George9-Oct-08 18:09

9-Oct-08 18:09

Thanks for your encouragement, I will continue my work. Smile | :)

regards,
George

CPallini9-Oct-08 22:05