Managed C++/CLI Discussion Boards

Can any "macro" take variable number of arguments?

Pradosh Tapan Datta2-Aug-06 22:49

Pradosh Tapan Datta

2-Aug-06 22:49

In C/C++ can any "macro" take variable number of arguments? Is it possible any way?

Pradosh

Re: Can any "macro" take variable number of arguments?

toxcct2-Aug-06 23:57

toxcct

2-Aug-06 23:57

depends of the compiler. with VC6, i'm sure you can't, but on later versions, i don't remember how you can do such macros though

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: Can any "macro" take variable number of arguments?

Michael Dunn4-Aug-06 14:10

Michael Dunn

4-Aug-06 14:10

Variadic macros[^]

--Mike--
Visual C++ MVP Cool | :cool:

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Re: Can any "macro" take variable number of arguments?

Pradosh Tapan Datta6-Aug-06 21:27

Pradosh Tapan Datta

6-Aug-06 21:27

It's working in VC++ 8. I could not check it in any other compiler.

Pradosh

Confusion about % vs. &

Joe Woodbury2-Aug-06 17:14

Joe Woodbury

2-Aug-06 17:14

% is for tracking references to CLI object
& is for passing native heap objects

If I use % and pass a native object, what is the compiled behavior? In other words given the following trivial example, does the code for x and y end up being the same, or does x box the passed value and then unbox it?

void Test(int% x, int& y)
{
  x++;
  y++;
}

void SomeFunction()
{
  int x = 0;
  int y = 1;
  // A bunch of stuff happens
  Test(x, y);
  // A bunch more stuff happens
}

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: Confusion about % vs. &

Michael Dunn4-Aug-06 17:47

Michael Dunn

4-Aug-06 17:47

Seems like x would automatically get boxed. You can run ildasm on the compiled binary and see if this is the case.
I could've sworn Nish had an article on & and % but I can't find it right now.

--Mike--
Visual C++ MVP Cool | :cool:

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Cin and Cout- Class or object

Shamnar2-Aug-06 1:46

Shamnar

2-Aug-06 1:46

hi friends,
i am infront of you with another doubt. We are using cin and cout in C++. Whether these are class or object.
if they are object how can we use them without declaring that it belongs to this class. Thanks for u in advance.
Shamnar Confused | :confused:

shamnar

Re: Cin and Cout- Class or object

NrmMyth2-Aug-06 5:52

NrmMyth

2-Aug-06 5:52

cin is a class...
well how do you percept a difference between class and object?

Re: Cin and Cout- Class or object

toxcct2-Aug-06 6:07

toxcct

2-Aug-06 6:07

NrmMyth wrote:
cin is a class

no, cin is an instance of a class (std::ofstream class).

the difference between a class and an object is that a class defines a type, while an object is an instance of that class (an instance of the type of the class)

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: Cin and Cout- Class or object

NrmMyth2-Aug-06 19:58

NrmMyth

2-Aug-06 19:58

my bad, weren't thinking

also, i never used word "object" for "instance", personal opinion

Re: Cin and Cout- Class or object

toxcct2-Aug-06 6:10

toxcct

2-Aug-06 6:10

well, i not only don't understand what you mean, but for the second time, i tell you that you ask about UNMANAGED C++, in a Managed C++ forum... this is the wrong place !

BTW, see my reply to the other guy to get some infos. the point is that cout and cin are instanciated at the beginning of your program (implicitely)

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: Cin and Cout- Class or object [modified]

gdoupanguoqing12-Aug-06 11:32

gdoupanguoqing

12-Aug-06 11:32

cin and cout aren't class or object. They are both functions.
we can use them without declaring because they have been declared in iostream.h

-- modified at 2:53 Sunday 13th August, 2006

-- modified at 2:55 Sunday 13th August, 2006

I love this web

eventhandlers created at run time for new menuitems

yiwpyos1-Aug-06 23:48

yiwpyos

1-Aug-06 23:48

Hi everyone!

I am creating menuitems on the main menu during run time from user instructions but i am stuck on creating eventhandlers for them at the same time.

I've tried specifying the eventhandler in the constructor like this

System::Windows::Forms::MenuItem * Item = new
System::Windows::Forms::MenuItem(S"subItem1",new
EventHandler(this,Item_Click));

(saw an example on the internet) but get

error C2065: 'Item_Click' : undeclared identifier
error C3350: 'System::EventHandler' : a delegate constructor expects two arguments

Any help is much appreciated

george

george

Splash Window in Managed C++

Pavan Rao1-Aug-06 21:34

Pavan Rao

1-Aug-06 21:34

Is there a way to have SPLASH WINDOW in VC++ .NET as in MFC ?
if not, any possible workaround ?

Cheers
Pavan

Re: Splash Window in Managed C++

prasad_som3-Aug-06 3:10

prasad_som

3-Aug-06 3:10

Pavan Rao wrote:
Is there a way to have SPLASH WINDOW in VC++ .NET as in MFC ?

do you mean in C#.

here is one.
http://www.codeproject.com/csharp/PrettyGoodSplashScreen.asp[^]

Re: Splash Window in Managed C++

Pavan Rao3-Aug-06 3:27

Pavan Rao

3-Aug-06 3:27

in C++, not C#

Defenition of library function

Shamnar1-Aug-06 1:03

Shamnar

1-Aug-06 1:03

Hi Experts,
As i am a beginer in C++ i met with a confusion. I would like to know where the actual defention of library function is present. For eg: the defention of strlen(). Is it present in string.h. Or just the declaration only present in the string.h. please clrify my doubts.
Thanking you
Shamnar

shamnar

Re: Defenition of library function

toxcct1-Aug-06 2:26

toxcct

1-Aug-06 2:26

strlen() is defined in the C runtime. it is not a function you should use in C++/CLI.

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: Defenition of library function

NrmMyth1-Aug-06 4:47

NrmMyth

1-Aug-06 4:47

I think you can't find the definition because they are compiled into library files.

Re: Defenition of library function

Shamnar1-Aug-06 18:17

Shamnar

1-Aug-06 18:17

thnks to both of u for spending your valuable time to reply a simple question like this.
Shamnar

shamnar

How to get the size of reference type structures

engsrini31-Jul-06 22:09

engsrini

31-Jul-06 22:09

Hello all,

How to get the size of reference type stucture,

ref Innerstruct<br />
{<br />
unsigned int j;<br />
bool bl;<br />
};<br />
ref stuct sample<br />
{<br />
int i;<br />
Byte b;<br />
Innerstruct st;<br />
};<br />
<br />
sample s=gcnew sample;<br />
int length=sizeof(s);

this returns 4, i thing it is the size of pointer. how to get the orginal size of structure and its members

creating special relations between tables

yiwpyos31-Jul-06 5:55

yiwpyos

31-Jul-06 5:55

Hi everyone!

I have an Access table made up of various "ingredients". From this table by selecting various "ingredients" i want to create another table (or just create new entries in another table) of "recipe" names and store this table in the same or another Access file.

I am connecting to the ingredients table and filling a dataset with it, through a DataAdapter, then i'm displaying the contents in a DataGrid in which i've added a CheckBox column. I'm planning to use this checkbox column to select the ingredients for the various recipes.

I know i can link such tables by using a column in the ingredients table which will specify a recipe name for each ingredient. However my problem is that some of the recipes will share the same ingredients so i can't use such a column to create the relationship.

Any ideas on the way to tackle this problem?

Thanks in advance.

Confused | :confused:

george

Re: creating special relations between tables

yiwpyos2-Aug-06 22:35

yiwpyos

2-Aug-06 22:35

Hi everyone,

I think i posted this one in the wrong Forum, so i posted it in the SQL/ADO/ADO.NET forum and got my answer thanks to ToddHileHoffer.

Will use three tables, one for the "recipes", one for the "ingredients" and one for the "recipeingredients" and the relation will be between the recipes table and the recipeingredients table. Just in case anyone else was wandering.

: )

cheeriooooo!

george

george

How to cast pointer from one type to another type

aloktambi31-Jul-06 2:05

aloktambi

31-Jul-06 2:05

i want to typecast System::Byte* to class type pointer
__gc class Update
{public:
unsigned short Posn;
short Pres;
short Temp1;
short Temp2;
Byte status;
};

Byte *data;
i am receieving data from one function

i want to typecast this Byte pointer to Update class pointer type.

how it is possible in managed c++

Re: How to cast pointer from one type to another type

HZ_7931-Jul-06 4:02

HZ_79

31-Jul-06 4:02

Hi,

I am not an expert, but I think the code below or a similar code should match:

Update* upd = new Update();
upd->Posn = data[0] + 256*data[1];
upd->Pres = data[2] + 256*data[3];
upd->Temp1= data[4] + 256*data[5];
upd->Temp2= data[6] + 256*data[7];
upd->status=data[8];

This is a simple way to do your cast by hand.

Thanks,

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