dev-cpp-users Mailing List for Dev-C++

Daniel Glenfield wrote:
> And I can't use a for loop and increment the pointer until it reaches 
> the end of the array because that is not safe, according to Code 
> Complete. Any more ideas? Maybe this isn't so easy after all! lol

As Per Westermark noted, correctly, the ONLY one safe method is to store 
the size separately.

Another (not so safe) alternative might be to use a special array 
element, which marks the end of the array. This is something, what 
char[] arrays use: the '\0' character, but you can use whatever you 
want. BUT, this method is not really the best, as getting the size 
requires you to iterate through the array, which can be very inefficient 
at large array sizes.

So, just store the size in a separate counter, that's how most people do 
it, there's no wrong about it, actually, that's the best known method 
nowadays. You can safely use it.

--
Greetings,
   Balázs

Hello,
I have wrapped an image library to make it Object Oriented, and now my 
static library is called vImage.lib (the library which is based on is 
instead a dll). Now, to test the library I have this example file in a 
new project, and I cannot debug it. It just doesn't perform the 
step-by-step debug.
To check if the project settings were ok I also used the "hello" example 
and pasted my code in it. Result: when I don't link to my library, 
everything worsk fine, as soon as link to it, it doesn't debug anymore.
Note that the problem doesn't affect only the code based on my library, 
but all the code (i.e. also the one of the "hello" example that worked 
before)
Note also that I have activated the generation of debug info when 
compiling the library as well.
What can I do?
thank you_ricky

And I can't use a for loop and increment the pointer until it reaches the 
end of the array because that is not safe, according to Code Complete. Any 
more ideas? Maybe this isn't so easy after all! lol


>From: Per Westermark <pw...@ia...>
>To: Mohammed Iqbal <mi...@ac...>
>CC: Daniel Glenfield <sp...@ho...>,      
><dev...@li...>
>Subject: Re: [Dev-C++] How to get the number of elements in an array
>Date: Tue, 20 Jan 2004 17:21:41 +0100 (CET)
>
>The idea was good, but it only works for statically allocated arrays.
>When the array is dynamically allocated, it isn't possible to check number
>of entries. Some low-level functions might return size of the memory block
>but that is highly nonportable, and it still doesn't answer number of
>array entries, since the allocated block will almost always be rounded up
>to a larger size.
>
>/Per W
>
>On Tue, 20 Jan 2004, Mohammed Iqbal wrote:
>
> > n_of_elements=sizeof(Buf)/sizeof(Buf[0]);
> >
> > Mohammed
> > ----- Original Message -----
> > From: "Daniel Glenfield" <sp...@ho...>
> > To: <dev...@li...>
> > Sent: Tuesday, January 20, 2004 1:49 PM
> > Subject: [Dev-C++] How to get the number of elements in an array
> >
> >
> > > This is an easy Q I know but I can't think how to do it...
> > >
> > > Size = 9;  // Decided by a function but set to 9 for this example
> > >
> > > int* Buf = new int[Size];
> > >
> > > int Tmp = sizeof(Buf);
> > >
> > > This can't be right. How do I get the size? Len(Buf) and Length(Buf) 
>are
> > not
> > > recognised (I thought they were functions but I guess not).
> > >
> > > Any thoughts?
> > >
> > > _________________________________________________________________
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The idea was good, but it only works for statically allocated arrays.
When the array is dynamically allocated, it isn't possible to check number
of entries. Some low-level functions might return size of the memory block
but that is highly nonportable, and it still doesn't answer number of
array entries, since the allocated block will almost always be rounded up
to a larger size.

/Per W

On Tue, 20 Jan 2004, Mohammed Iqbal wrote:

> n_of_elements=sizeof(Buf)/sizeof(Buf[0]);
>
> Mohammed
> ----- Original Message -----
> From: "Daniel Glenfield" <sp...@ho...>
> To: <dev...@li...>
> Sent: Tuesday, January 20, 2004 1:49 PM
> Subject: [Dev-C++] How to get the number of elements in an array
>
>
> > This is an easy Q I know but I can't think how to do it...
> >
> > Size = 9;  // Decided by a function but set to 9 for this example
> >
> > int* Buf = new int[Size];
> >
> > int Tmp = sizeof(Buf);
> >
> > This can't be right. How do I get the size? Len(Buf) and Length(Buf) are
> not
> > recognised (I thought they were functions but I guess not).
> >
> > Any thoughts?
> >
> > _________________________________________________________________
> > Use MSN Messenger to send music and pics to your friends
> > http://www.msn.co.uk/messenger
> >
> >
> >
> > -------------------------------------------------------
> > The SF.Net email is sponsored by EclipseCon 2004
> > Premiere Conference on Open Tools Development and Integration
> > See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
> > http://www.eclipsecon.org/osdn
> > _______________________________________________
> > Dev-cpp-users mailing list
> > Dev...@li...
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> >
>
>
>
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n_of_elements=sizeof(Buf)/sizeof(Buf[0]);

Mohammed
----- Original Message -----
From: "Daniel Glenfield" <sp...@ho...>
To: <dev...@li...>
Sent: Tuesday, January 20, 2004 1:49 PM
Subject: [Dev-C++] How to get the number of elements in an array


> This is an easy Q I know but I can't think how to do it...
>
> Size = 9;  // Decided by a function but set to 9 for this example
>
> int* Buf = new int[Size];
>
> int Tmp = sizeof(Buf);
>
> This can't be right. How do I get the size? Len(Buf) and Length(Buf) are
not
> recognised (I thought they were functions but I guess not).
>
> Any thoughts?
>
> _________________________________________________________________
> Use MSN Messenger to send music and pics to your friends
> http://www.msn.co.uk/messenger
>
>
>
> -------------------------------------------------------
> The SF.Net email is sponsored by EclipseCon 2004
> Premiere Conference on Open Tools Development and Integration
> See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
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> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
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>

I tried that but it returns the size of the first element in the array (or 
whatever the pointer is pointing to).
To set Size I called a function and it returns 320 (bytes required). This is 
most troubling as I should know this! lol

Daniel


>From: "Paul Muehlbach" <tr...@gm...>
>To: "Daniel Glenfield" <sp...@ho...>
>Subject: Re: [Dev-C++] How to get the number of elements in an array
>Date: Tue, 20 Jan 2004 14:04:00 +0100 (MET)
>
> > This is an easy Q I know but I can't think how to do it...
> >
> > Size = 9;  // Decided by a function but set to 9 for this example
> >
> > int* Buf = new int[Size];
> >
> > int Tmp = sizeof(Buf);
> >
> > This can't be right. How do I get the size? Len(Buf) and Length(Buf) are
> > not
> > recognised (I thought they were functions but I guess not).
> >
> > Any thoughts?
> >
>
>try
>
>Tmp = sizeof(*Buf);
>
>(sorry,but normally,i use c-array functions ^^°)
>
>traexx
>
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In short - you can't.

sizeof(Buf) will return sizeof(int*) i.e. the size of a pointer.

There is no way of requesting the size of a dyanmically allocated array.
You must store the size somewhere else, such as:

struct {
    int size;
    int *ptr;
} Buf;

Buf.size = 9;
Buf.ptr = new int[Size];

/Per W

On Tue, 20 Jan 2004, Daniel Glenfield wrote:

> This is an easy Q I know but I can't think how to do it...
>
> Size = 9;  // Decided by a function but set to 9 for this example
>
> int* Buf = new int[Size];
>
> int Tmp = sizeof(Buf);
>
> This can't be right. How do I get the size? Len(Buf) and Length(Buf) are not
> recognised (I thought they were functions but I guess not).
>
> Any thoughts?
>
> _________________________________________________________________
> Use MSN Messenger to send music and pics to your friends
> http://www.msn.co.uk/messenger
>
>
>
> -------------------------------------------------------
> The SF.Net email is sponsored by EclipseCon 2004
> Premiere Conference on Open Tools Development and Integration
> See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
> http://www.eclipsecon.org/osdn
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
>

This is an easy Q I know but I can't think how to do it...

Size = 9;  // Decided by a function but set to 9 for this example

int* Buf = new int[Size];

int Tmp = sizeof(Buf);

This can't be right. How do I get the size? Len(Buf) and Length(Buf) are not 
recognised (I thought they were functions but I guess not).

Any thoughts?

_________________________________________________________________
Use MSN Messenger to send music and pics to your friends 
http://www.msn.co.uk/messenger

Thank you ageofscot,
that will help me very much to focus in what i am trying to do.

Excellant :-)

----- Original Message -----
From: <age...@co...>
To: "DevCpp User Group" <dev...@li...>; "RUDOLPH"
<ku...@sp...>
Sent: Monday, January 19, 2004 6:52 PM
Subject: Re: [Dev-C++] HELP: in MSW testing program for Linux


> The only way I know:
> 1. Write the code with Dev-C++.
> 2. Transfer it to some removable storage device or a server.
> 3. Compile the code on that platform.
>
> --
> ~~Scott Simontis~~
> Programmer
>
>

Hello Michael,
Thank you your reply.
What I was thinking about was
to compliing  a source  code after the  designing stage in w95 platform and
then complie the same source code in another miniLinux computer with Devc++
or Gnu complier.

Your answer have been helpful.

Kind regards

----- Original Message -----
From: "Michael C Urban" <mu...@cb...>
To: "RUDOLPH" <ku...@sp...>
Cc: <dev...@li...>
Sent: Monday, January 19, 2004 12:37 AM
Subject: Re: [Dev-C++] HELP: in MSW testing program for Linux


> What do you mean?
>
> Basically, you can't, unless you use WINE or some other emulator in Linux
> to run the program. DevC++ works with MinGW, which generated machine code
> for MS Windows. It won't run on Linux.
>
> To make the program run on Linux, you would have to recompile it using
> GCC on Linux, which may or may not be an easy task depending on whether
> the source code in question uses the Windows API.
>
> Mike
>
> On Mon, 19 Jan 2004, RUDOLPH wrote:
>
> > New year greeting to u all!
> >
> > Has anyone able to complied program using
> > DevC++ in MS windows, and use or test it into
> > other OS like linux ?
> >
> > Thank you in advance.
> > Rudy
> >
>