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This is the C++/CLI forum. For C++/CLI, the answer is yes. For C++, the answer is no.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
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I am developing this simple arithmetic program and this is my first windows application ever, so I am not so sure at how to program this. In my app the user can set the lower limit and upper limit for the calculations numbers that are about to come up in a test the user want’s to do. You se the upper and lower limit as variables in the code below. The code below generates calculations for addition, subtraction and multiplication. So let us suppose that the user sets the limits to lower = 1 and upper = 100, that will give us 100 x 100 = 10 000 calculations! When I test this on my own computer it takes a while to generate all calculations, and if I change upper limit = 200 the program stops I push (ctrl+alt+del) and it says that the application is not responding.
// Generating all Calculations for addition, subtraction and multiplication
for(int i = lowerLimit; i <= upperLimit; i++)
{
for(int j = lowerLimit; j <= upperLimit; j++)
{
// Reset flag
excludeCalculation = false;
// Create temp Calculation
tempCalculation = gcnew Calculation(i, calculationOperator, j);
// Check if Calculation should be removed
excludeCalculation = this->removeCalculation(tempCalculation);
// Check if to add Calculation
if(excludeCalculation == false) // If NOT to be excluded
{
calculations->Add(tempCalculation);
}
}
}
How do I prevent the application from stopping like this??
I would like to show a progressbar while the application is generating the calculations, but I don’t know how to do this when the application get hung up by it self all the time, I can not figure out how to work around this problem.
Does anybody have any tips???
I am not so familiar with using Threads, but is this one of these occasions when I should be using Threads???
If so, can someone give me an example of how to program with treads?? And how do I pass data between threads?… I have to know how many calculations is generated for my progressbar… or??
I am a complete newbe on this… so all help is appreciated!!
Best regards, Andreas
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AAsterlund wrote: I am a complete newbe
What made you choose C++/CLI ? C# or proper C++ seem like better places to start, to me.
Have you set a breakpoint to step through and work out where your program is getting stuck ? You can also choose "break all" from the debug menu while running in debug mode, and the code will stop where it's stuck.
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
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Christian Graus wrote: What made you choose C++/CLI ? C# or proper C++ seem like better places to start, to me.
Have you set a breakpoint to step through and work out where your program is getting stuck ? You can also choose "break all" from the debug menu while running in debug mode, and the code will stop where it's stuck.
First of all I want to say that I am NOT a professional programer that develops applications on a day to day basis. And I am NOT a master in Visual C++ either (and I am not used to work with the debugger, but I like to learn it some time when I got som time left over for it). Programming is only a hobby of mine that I like to practise only on my spare time. I like the fact that one could develop applications, that can be used to ease the burden in various occasions in life.
In the past I have had 1-2 months of education in native C++ (that is developing in a dos environment and not using any development tool, only notepad). Later I wanted to develop some windows application and I needed a development tool and I chose Microsoft Visual Studio 2005. And it felt natural for me to go from native C++ to C++/CLI. I mean I knew a little C++ and managed C++ seemed to me to be a good technology, so I went with that!
And yes I am a complete newbe on thread-programming... I have never had to use it before.
So instead of moralizing about what is the right place or not for me to start developing my little interest in programming, it would be a lot more helpful and less timeconsuming for both me and you if you just could give me answers to my questions! I am not asking for you or anybody else to write my program for me, that I want to do on my own. I just need help, tips or derections on how to proceed from here.
As you maybe have noticed I am not used to the debugger due to the small complexity of my applications. Maybe it is foolish of me not to use it, but if I got more time left over I would try to learn it. It seems to be a good help in development, but that is not the question here I think.
I put a messagebox before and after this particular code snippet and only the one before showed up before the application got hung up. The one after showed up only after I had removed the the loops from the code. So I think I am fairly sure that this is where my program is getting stuck, don't you think??
I think I must run the code in another thread and I was thinking about showing a dialog with a progressbar on how many calculations is left to generate before the test dialog is shown. Should I run the dialog with the progressbar in the same thread as the one I am generating calculations in??
I am little confused about how to think here...
best regards, Andreas
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AAsterlund wrote: So instead of moralizing about what is the right place or not for me to start developing my little interest in programming, it would be a lot more helpful and less timeconsuming for both me and you if you just could give me answers to my questions!
I'm sorry, I'm just trying to help. C++/CLI is a lot harder than C#, and not widely supported. If you follow this path, you'll find it hard to get much help, which is why I commented.
AAsterlund wrote: Maybe it is foolish of me not to use it, but if I got more time left over I would try to learn it.
Using the debugger is a basic skill, you're not going to get far without it. Just press F9 or right click to set a breakpoint. Then press F5 and the code will stop at the breakpoint, you can then single step through code, and type in variable names and expressions in the Watch window to see what your program is doing. Until you learn that, you're just stabbing in the dark
AAsterlund wrote: I put a messagebox before and after this particular code snippet and only the one before showed up before the application got hung up.
OK, then it's getting stuck in the loop. If you press the break all under the debug menu, you'll see which line it's on, and be able to see the values of your various variables. You can also put console.writeline statements inside the loop and they will appear in the output window.
AAsterlund wrote: don't you think??
I had no doubt, I was advocating you step into the code to work out *why*
AAsterlund wrote: I think I must run the code in another thread
It shouldn't take very long, this code. You don't need another thread every time you write a nested loop
AAsterlund wrote: Should I run the dialog with the progressbar in the same thread as the one I am generating calculations in??
No, all UI must be in the same thread, that's the point. The UI remains responsive while the background thread does the work.
AAsterlund wrote: I am little confused about how to think here...
I'm sure if you step into the code with the debugger, you can solve this in less time than it took you to reply to my post.
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
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Christian Graus wrote: I'm sorry, I'm just trying to help. C++/CLI is a lot harder than C#, and not widely supported. If you follow this path, you'll find it hard to get much help, which is why I commented.
Okey it seems to be a missunderstanding of mine. And I certainly don't want argue with you. Tanks for the help!
best regards, Andreas 000 the computer got hung up. And when I changed the lower and upper values to -10000 and 10000 I got this message:
"An unhandled exception of type 'System.OutOfMemoryException' occurred"
Does this mean that my computer can not generate all calculations between -10000 and 10000 (like: 10000 - 7893, -8512 - 2113, 9875 - 3213 and so on...)??
I would have hoped for my application to being able to generate calculations up to at least 100000 and maybe up to 1000000.
If it is to any help for you, my computer specifications are:
AMD Athlon XP 2200+ 1.80 GHz
512 MB RAM
Under given circumstances; is my computer to slow or is there a bug in my code??
best regards, Andreas
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When the OS says "not responding," that just means that the app has stopped processing window messages. If you watch task manager, you'll see that the thread is still using CPU time.
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Yeah, good point.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
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Hello,
One thing I dislike about C++/CLI is that using Designer for forms most often ruins my formatting of the code. C# has a good solution against that, which is the partial keyword, allowing me to write my part of code cleanly while the generated mess resides in another file.
Is partial keyword going to be implemented in any of the upcoming C++/CLI versions?
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Microsoft is attempting to keep C++/CLI close to the standard as possible. Thus, the concept behind the "partial" keyword goes against the current C++ standard, and Microsoft will not make any attempt to support the "partial" class concept. By the way, the upcoming C++ standard will not support this concept also.
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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George L. Jackson wrote: Microsoft is attempting to keep C++/CLI close to the standard as possible. Thus, the concept behind the "partial" keyword goes against the current C++ standard
I cannot see how ^ or finalizers are closer to C++ standard than the partial keyword would be. The influence of partial to the compiler is perhaps much smaller than this of already introduced keywords, isn't it?
BTW, you may want to take a look at "C++ divided by CLI"[^] by Dominic Connor.
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The "^" and finalizers have a swallow impact on the overall behavior of C++. However, partial classes impact on how the compiler works and the behavior of OOP in general. The problem is how would you create partial classes following C++ rules. IMHO, combining partial classes is similar to public inheritance without a base or derived class. That concept is very alien to C++.
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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OK then, how about getting some control over the formatting of generated code? Any chance?
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Unfortunately, I don't think we have any options unless you format the code afterwards, and, thus, breaking any hope of creating more generated code. 
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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partial classes are an attempt to catch up with C++. You can split a class into multiple cpp files now, managed, or otherwise.
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
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Yes, you can split a C++ class among multiple C++ files. However, a "partial" class in C# and VB acts more like a namespace since one or more partial classes combine fields and function members in one set. In contrast, you must a least declare a member function in a C++ class declaration, and define the member functions in the class declaration or someplace else.
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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The real difference is, the C++ has a header file, and C# and VB.NET do not. Once you have a header file, I don't see how the multiple C++ cpp files behave any different, except that in the absence of a header file, you can keep adding files to extend a partial class, without having to maintain a central interface definition.
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
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Christian Graus wrote: ..., except that in the absence of a header file, you can keep adding files to extend a partial class, without having to maintain a central interface definition.
That's the difference!
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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Christian Graus wrote: I don't see how the multiple C++ cpp files behave any different
Well, .cpp is not an issue. The Designer smashes the one and only .h file of a control or a form. Maybe my coding standard is inconsistent with Microsoft's, but those intrusions make a real mess there. Either should they be placed in a separate file (using an extension similar to the C# partial keyword), or Designer should provide a powerful configuration facility for code generation, where I should define my preferred style in the form of some template. Adding such functionality shouldn't be a real problem.
May you have any XAML/C++ interop experience? Are these issues still present in Orcas? I haven't had a chance to play with it yet.
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In Unix Operating System,how to create messagebox window with Button using c language or c++.Give example program with output.
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C++/CLI is not supported on an Unix OS. You will have better luck asking this question in the Visual C++ forum. However, please note that the Visual C++ forum is a Windows OS based forum.
"We make a living by what we get, we make a life by what we give." --Winston Churchill
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Hi,
I'm pretty new to programming in C++ (got some PHP/MYSQL exp.).
But I'm trying to make a program now(not important), but I want to check if they registerd their version trough a mysql database.
This is (empty) function that i'm going to use
int user_check(string user_reg, string user_pass, string account_name)<br />
{<br />
if(var4 != "yes")<br />
{<br />
user_checked = 1;<br />
}<br />
return user_checked;<br />
}
So what I want to know is how to make a connection with a database, then get the results from a table(ex. members).
please help me out
(If you include files, give me (a) link(s) where I can get them all)
I'm using Dev-C++ to compile
Thanks in advance
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iLLeLogicaL wrote: I'm using Dev-C++ to compile
Then you are, by definition, not using C++/CLI.
There is no database support in C++, it's all provided by external libraries. Any answers you get in the Visual C++ forum, are likely to be Microsoft Visual Studio centric. You could try there, it's better than asking here, but I'm not confident. Have you tried google ?
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
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http://dev.mysql.com/downloads/connector/
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Yes and it brought me to this post
http://www.codeproject.com/database/mysqlwrap.asp but when I try to compile it always gives the error that mysql.h isn't included. Even when it is in the main program. I copied the whole include map of a mysqlserver (4.1) to the same map where mysqlplus.h is :-/
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