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What are the values of wParam and lParam, and what assertion did you receive?
The best things in life are not things.
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NO.
Just send BM_CLICK (!)
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hi all....! i got a project to make compressor like winrar on mfc which can compress or decompress any file.... pls let me know what i have to do for it.....! how to start it ...!~
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You could start off by reading about Data Compression[^], and when you have a specific question ask again here.
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hmaz4629 wrote: i got a project...
Personal or school?
"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
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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Ok, so what preliminaries has your instructor given? Since academic coding is usually comprehensive, what other assignments have you completed that this one will build upon? Have you asked your instructor for guidance?
"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
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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well my constructor just told me that you have to make a compression on mfc and the thing you will use is to assign lowest frequency to the highest occuring number or digit or character or anything .
the code type you have to write is called huffman code
it is a type of tree which has branches
mean each linklist bo have link of two next boxes.
i have started using MFC week ago
and i have chosen this project because i need bonus to improve my grade
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hmaz4629 wrote: well my constructor just told me...
When your constructors start talking to you, it's time for a break! 
"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
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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Since you have posted the question in MFC forum i think you WANT CODE IN mfc.Read about data compression and look at this opensource compressor for reference.(learn and develop don't copy it  )
7 ZIP:
http://sourceforge.net/projects/sevenzip/[^]
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yeah i wanna learn not to copy thanks
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hmaz4629 wrote: how to start it
I usually start projects using the File/New/Project menu command. Have you tried that yet? 
Chris Meech
I am Canadian. [heard in a local bar]
In theory there is no difference between theory and practice. In practice there is. [Yogi Berra]
posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
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In the past I have often had to do this - ie compress data/files. The best way is to use zlib as it is a defacto standard, open-source, unencumbered by any patents/licensing limitations and is supported in a large number of languages and environments. See http://zlib.net/[^].
You can also use my open source hex editor to play with all the options and features without writing any code. See HexEdit - Window Binary File Editor[^].
Andrew Phillips
http://www.hexedit.com
andrew @ hexedit.com
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Please clear the below confusion;
1. Can you call "delete this;" inside a member function?
2. If Yes, What can you do after calling delete this?
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It is allowed, but wreaks all kind of havoc depending on what the next statements are in your code.
An object instance didn't instantiate itself, so it should neither delete itself. There might still be refernces pointing to said ojbect instance which would become undefined if the object instance would delete itself.
Best Regards,
-MRB
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u can do this but after this you cant access that mamber function or veriable which is being deleted....!~
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hmaz4629 wrote: u can do this but after this you cant access that mamber functio
Technically that depends on the exact nature of the function and maybe the compiler.
I say maybe because I would suppose that most C++ compilers are going to generate static bindings for non-virtual methods simply because it produces faster code.
hmaz4629 wrote: or veriable which is being deleted..
That is certainly unsafe but the actual impact depends again on the compiler and what the variable is and how the application works.
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You can do that, but with care!
Afterwards you can not access any instance variables. This implies you can call class methods (declared static) and also other instance methods as long as they don't access any instance variables (in which case they are not truly instance methods anyway.) You can still access class variables (declared static).
My recommendation is to not use it unless you really know what you're doing.
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I think this is one of those things you can do but shouldn't.
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You can and it might even work.
It however is always wrong.
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jschell wrote: It however is always wrong.
Not always.
"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
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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Odd.
Myself I would consider the design that lead to that requirement wrong.
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This can be used to clean up when implementing COM objects in C++. E.g. when the reference count is zero in Release().
It puts some constraints on instance creation though. You will not get away with automatic objects for instance.
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Like others have said, you cannot access instance member variables after delete this.
In addition, I would like to mention that if the object is created on the stack, it will crash.
So before you do this you have to ensure that the object is created on the heap.
You could probably do this on a singleton implementation.
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You can, but you normally shouldn't. You'll destroy both the variables and the virtual function table (if you have one), so cannot access either. The only things you could still safely do is call static member functions or access static member variables.
That said...:
- What would happen if you allocated an array of objects of this type? -> crash!
- What would happen if you allocated the object on the stack, not on the heap? -> crash!
- What would happen if you allocated an object through malloc, a pool allocator, or any other non-standard memory allocator?
-> most likely crash
- What would happen if you allocated an object of a class derived from this one? -> might work, but could have undesired effects as you're calling the derived class' delete function which may do more than you intended
The only way to define such a class in a way that prevents any of the uses above is by protecting access to all the constructors and the destructor, and then provide create() and destroy() functions instead. Or use a friend helper class that does it for you (e. g. smart pointer or factory)
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