C / C++ / MFC Discussion Boards

PJ Arends23-Feb-11 11:31

23-Feb-11 11:31

--number changes the value of number, number - 1 does not.

say number is 10:
sum(number - 1) + number; is sum(9) + 10;

and
sum(--number) + number; is sum(9) + 9;

You may be right
I may be crazy
-- Billy Joel --

Within you lies the power for good - Use it!

Re: --i not equal to i - 1 ???

Cristoff23-Feb-11 11:47

Cristoff

23-Feb-11 11:47

The first line was enough! Thank you very much! Sometimes, well maybe most of the time I'm so stupid. That's so obvious!

Re: --i not equal to i - 1 ???

Peter_in_278023-Feb-11 12:23

Peter_in_2780

23-Feb-11 12:23

Being a bit pedantic here (but it's necessary!)...

Since the order of evaluation is not defined by the language spec, the compiler writer is free to choose, so your second example
sum(--number) + number; could come out either way (but number will always wind up decremented). There are lots of examples of confusion over this.

Cheers,
Peter

[edit]formatting[/edit]

Software rusts. Simon Stephenson, ca 1994.

yes the value of --i equals that of i - 1 however the side effects are different

Luc Pattyn23-Feb-11 13:36

Luc Pattyn

23-Feb-11 13:36

I concur, at least for C. I just don't know for recent versions of C++.
And I would never write a statement like that.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.

Re: yes the value of --i equals that of i - 1 however the side effects are different

Stefan_Lang24-Feb-11 1:59

Stefan_Lang

24-Feb-11 1:59

According to this list, item 31 (on the table of contents), it is true for C++ as well.

Key pressed time Logic

manchukuo23-Feb-11 9:29

manchukuo

23-Feb-11 9:29

Hello

i am currently facing this problem, i am doing a kind of game where when the user presses a key like the 'a' key it makes jump the object, but how to detect key press in a way to know how much jump, if you press the key for a tiny time do a little jump or if you got pressed the button too much jump only a maximum.

Thanks

Re: Key pressed time Logic

David Crow23-Feb-11 9:32

David Crow

23-Feb-11 9:32

Check out the WM_KEYUP and WM_KEYDOWN messages.

"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

Re: Key pressed time Logic

manchukuo23-Feb-11 10:12

manchukuo

23-Feb-11 10:12

i know about this ones but how to get the time or do the logic for doing what i asked?

Re: Key pressed time Logic

David Crow23-Feb-11 10:18

David Crow

23-Feb-11 10:18

Did you read the documentation, specifically about bits 0-15 of the LPARAM parameter?

Re: Key pressed time Logic

manchukuo23-Feb-11 10:20

manchukuo

23-Feb-11 10:20

Oh i see, i wasn't reading the MSDN documentation :p

unresolved external symbol error when i compile my win32 app

smishtiaqhussain23-Feb-11 1:53

smishtiaqhussain

23-Feb-11 1:53

I am new at c++, and ;I am trying to use existing library that contains .c and .h files.This library also contain one test program.I have included all .c and .h files to my project. When i try to build my project I get the about 10 different "LNK2019: unresolved external symbol errors". maybe some one can help me figure this out.I have checked that .c and .h files contain these function i-e mzd_copy,mzd_echelonize_m4ri etc. I am using visual studio C++ .net 2008. I have uploaded my project at mediafire
http://www.mediafire.com/?6bcuo1tmg3smysc

the error i received are as follows:

Error	7	error LNK2019: unresolved external symbol _mzd_copy referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	6	error LNK2019: unresolved external symbol _mzd_echelonize_m4ri referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	4	error LNK2019: unresolved external symbol _mzd_echelonize_naive referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	3	error LNK2019: unresolved external symbol _mzd_echelonize_pluq referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	2	error LNK2019: unresolved external symbol _mzd_equal referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	1	error LNK2019: unresolved external symbol _mzd_free referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	9	error LNK2019: unresolved external symbol _mzd_init referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	8	error LNK2019: unresolved external symbol _mzd_randomize referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	5	error LNK2019: unresolved external symbol _mzd_top_echelonize_m4ri referenced in function "int __cdecl elim_test_equality(int,int)" (?elim_test_equality@@YAHHH@Z)	test_elimination.obj
Error	10	fatal error LNK1120: 9 unresolved externals	C:\Users\Ishtiaq\Documents\Visual Studio 2008\Projects\test333\Debug\test333.exe

Re: unresolved external symbol error when i compile my win32 app

_AnsHUMAN_ 23-Feb-11 1:56

_AnsHUMAN_

23-Feb-11 1:56

Your function definition might be a mismatch with the function declaration. Make sure you are using the correct prototype.
The linker error indicates that your code is unable to find a matching function.

I am a HUMAN. I have that keyword in my name........
Wink | ;-)

<marquee>_AnsHUMAN_</marquee>

Re: unresolved external symbol error when i compile my win32 app

Richard MacCutchan23-Feb-11 2:02

Richard MacCutchan

23-Feb-11 2:02

Check the source file that contains all the functions with the _mzd_ prefix is being correctly compiled and included in the project.

I must get a clever new signature for 2011.

Re: unresolved external symbol error when i compile my win32 app

tagopi23-Feb-11 2:03

tagopi

23-Feb-11 2:03

hello,

i am not able to download your project from the link you gave. anyway, is there any lib file and if so, did you include that in project settings->linker....

Regards,
A. Gopinath.

Re: unresolved external symbol error when i compile my win32 app

smishtiaqhussain23-Feb-11 2:35

smishtiaqhussain

23-Feb-11 2:35

Hi,
Thank you everybody for the quick feedbacks.

Here is the link again. Its working.
http://www.mediafire.com/file/6bcuo1tmg3smysc/test333.rar[^]

I have confirmed that all of the implementations used in my test project are available in the source and their corresponding header files.
I have added all the required files to to my source and header folders of my project.
There are no pre-compiled .lib or .dll files. I have got all the necessary files in .c and .h format. The library also has extern C symbols added so that it can be compiled as a C++ code.
I can easily jump to function implementation in header file using "Go to definition" in VC++ editor from my test .cpp source file. But still nonetheless i am getting linking errors.
Kindly please have a look at the project source.

Thanks a million Smile | :)

Regards,

Re: unresolved external symbol error when i compile my win32 app

Richard MacCutchan23-Feb-11 3:18

Richard MacCutchan

23-Feb-11 3:18

Please see my previous message. Your project has not included the files in the m4ri folder so the mzd functions are not being compiled. You should either add all these source files to your project, or create a project that compiles them into a .lib file (static library), and add that to your main project.

I must get a clever new signature for 2011.

Re: unresolved external symbol error when i compile my win32 app

smishtiaqhussain23-Feb-11 21:25

smishtiaqhussain

23-Feb-11 21:25

Hi,
Thanks a lot for your quick reply.All of my .c and .h files are available in m4ri folder.
Will you please tell me that how I can create project that compiles them into a .lib file(static library), and how can I can add that to my main project.

Thanks a lot.
Regards,
Ishtiaq

Re: unresolved external symbol error when i compile my win32 app

Richard MacCutchan23-Feb-11 22:33

Richard MacCutchan

23-Feb-11 22:33

Yes, I know they are available in the folder but unless you compile them into object code your program will never be built successfully. If you do not know how to create such a project then I suggest you go to the Visual Studio help pages and read up on the compiler and linker options for building different project types.

I must get a clever new signature for 2011.

Re: unresolved external symbol error when i compile my win32 app

tagopi23-Feb-11 16:47

tagopi

23-Feb-11 16:47

hello,

i can able to download now. i saw your project.
Mr. Richard is right. do as he said, then you will get the result.

Regards,
A. Gopinath.

Need assistance on how to send emails in VC6

John50223-Feb-11 1:07

John502

23-Feb-11 1:07

Hi,
Need assistance on how to send emails with attachment in VC6.0 environment...
I don't want to get any kind of alert while sending email with attachment...

Kindly assist on this..

Thanks
John

Re: Need assistance on how to send emails in VC6

_AnsHUMAN_ 23-Feb-11 1:58

_AnsHUMAN_

23-Feb-11 1:58

MAPI[^]

I am a HUMAN. I have that keyword in my name........
Wink | ;-)

<marquee>_AnsHUMAN_</marquee>

Re: Need assistance on how to send emails in VC6

Rolf Kristensen23-Feb-11 6:41

Rolf Kristensen

23-Feb-11 6:41

Consider launching an external program like bmail[^]

CFileDialog default path

john563223-Feb-11 1:06

john5632

23-Feb-11 1:06

Can I show deafult path "My Computer" for CFileDialog() ?

Re: CFileDialog default path

Richard MacCutchan23-Feb-11 1:59

Richard MacCutchan

23-Feb-11 1:59

What happens when you try it?

I must get a clever new signature for 2011.

Re: CFileDialog default path

Maximilien23-Feb-11 2:36

Maximilien

23-Feb-11 2:36

Yes.

Initialize it by updating the m_ofn (OPENFILENAME) structure with the appropriate path.

the "my document" can be found with SHGetFolderPath.

Watched code never compiles.

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