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From: Mike Copeland on 30 Apr 2010 13:56
I'm trying to declare and define a variable array - one which I
intend to populate, sort and access via a binary search. My problem is
that I cannot seem to convert scalar type dynamic allocation to that of
a structure I've created. Here's my structure:

struct dbeStruct
{
int bibNumber;
char source;
string body;
} dbeWork;

Here's my code attempt to define a dynamic array of this data:

dbeStruct *dbeZeroBibs = NULL;
dbeZeroBibs = new dbeStruct[2505];

I don't know what I've done wrong, and I don't understand the error
diagnostic (C2501) I'm getting from the (VS6.0) compiler. Please
advise. TIA
From: Victor Bazarov on 30 Apr 2010 14:46
On 4/30/2010 1:56 PM, Mike Copeland wrote:
> I'm trying to declare and define a variable array - one which I
> intend to populate, sort and access via a binary search. My problem is
> that I cannot seem to convert scalar type dynamic allocation to that of
> a structure I've created. Here's my structure:
>
> struct dbeStruct
> {
> int bibNumber;
> char source;
> string body;
> } dbeWork;

What's 'dbeWork'? You're defining an object here where you define the
struct?

>
> Here's my code attempt to define a dynamic array of this data:
>
> dbeStruct *dbeZeroBibs = NULL;
> dbeZeroBibs = new dbeStruct[2505];
>
> I don't know what I've done wrong, and I don't understand the error
> diagnostic (C2501) I'm getting from the (VS6.0) compiler. Please
> advise. TIA

Post the shortest example that gives you that error, then post the
*exact* compiler diagnostic. Consider that while some of us may still
have VC6 lying around, it's likely that we don't have the ability to use
*that* old of a compiler to try your code. BTW, why don't you upgrade?

Also, why don't you use 'std::vector<dbeStruct>' instead of the dynamic
array? It's so much easier to let the Standard Library functionality
handle dynamic memory allocation...

V
--
I do not respond to top-posted replies, please don't ask
From: Mike Copeland on 30 Apr 2010 17:31
> > I'm trying to declare and define a variable array - one which I
> > intend to populate, sort and access via a binary search. My problem is
> > that I cannot seem to convert scalar type dynamic allocation to that of
> > a structure I've created. Here's my structure:
> >
> > struct dbeStruct
> > {
> > int bibNumber;
> > char source;
> > string body;
> > } dbeWork;
>
> What's 'dbeWork'? You're defining an object here where you define the
> struct?
Yes, I'm defining an object variable of the struct type. Is there
something wrong with that?
> >
> > Here's my code attempt to define a dynamic array of this data:
> >
> > dbeStruct *dbeZeroBibs = NULL;
> > dbeZeroBibs = new dbeStruct[2505];
> >
> > I don't know what I've done wrong, and I don't understand the error
> > diagnostic (C2501) I'm getting from the (VS6.0) compiler. Please
> > advise. TIA
>
> Post the shortest example that gives you that error, then post the
> *exact* compiler diagnostic.
I will do that, in a followup post.

> Consider that while some of us may still
> have VC6 lying around, it's likely that we don't have the ability to use
> *that* old of a compiler to try your code. BTW, why don't you upgrade?
Because I can't afford to purchase a new version...and 6.0 is all I
have. Also, I'm quite old and I tend to be leary of the effort to
upgrade to something (conversions, porting of existing
code/applications) that is unknown. Yes, that's not a good argument,
but I have ~1,000,000 lines of code and upgrading to (what?) is very
daunting.

> Also, why don't you use 'std::vector<dbeStruct>' instead of the dynamic
> array? It's so much easier to let the Standard Library functionality
> handle dynamic memory allocation...
As I understand it, I'd need a scalar index for a vector. The data I
will be storing in my array doesn't have unique values in either the
"bibNumber" or "source" fields, and my application will be working only
with the "body" values: sorting and searching. Perhaps there's another
way, but the volume here is rather high and seems to call for a binary
search. <sigh...>
From: Mike Copeland on 30 Apr 2010 17:48
> > struct dbeStruct
> > {
> > int bibNumber;
> > char source;
> > string body;
> > } dbeWork;
>
> What's 'dbeWork'? You're defining an object here where you define the
> struct?
>
> >
> > Here's my code attempt to define a dynamic array of this data:
> >
> > dbeStruct *dbeZeroBibs = NULL;
> > dbeZeroBibs = new dbeStruct[2505];
> >
> > I don't know what I've done wrong, and I don't understand the error
> > diagnostic (C2501) I'm getting from the (VS6.0) compiler. Please
> > advise. TIA
>
> Post the shortest example that gives you that error, then post the
> *exact* compiler diagnostic. Consider that while some of us may still
> have VC6 lying around, it's likely that we don't have the ability to use
> *that* old of a compiler to try your code. BTW, why don't you upgrade?

Here's a complete program that demonstrates the problem, as well as
all error diagnostics. TIA
#include <iostream>
#include <string>
using namespace std;
struct dbeBuild
{
int bibNumber;
char source;
string body;
} dbeWork;

dbeBuild *dbeZeroBibs = NULL;
dbeZeroBibs = new dbeBuild[2505]; // the errors are on this line
// error C2501: 'dbeZeroBibs' : missing storage-class or type specifiers
// error C2040: 'dbeZeroBibs' : 'int' differs in levels of indirection
from 'struct dbeBuild *'
// error C2440: 'initializing' : cannot convert from 'struct dbeBuild
*' to 'int'
// This conversion requires a reinterpret_cast, a C-style cast or
function-style cast
// Error executing cl.exe.
// dynarray.exe - 3 error(s), 0 warning(s)

int main(int argc, char *argv[]) ////////// M A I N L I N E
////////
{

return 0;
}

From: Thomas J. Gritzan on 30 Apr 2010 17:54
Am 30.04.2010 23:48, schrieb Mike Copeland:
> Here's a complete program that demonstrates the problem, as well as
> all error diagnostics. TIA
> #include <iostream>
> #include <string>
> using namespace std;
> struct dbeBuild
> {
> int bibNumber;
> char source;
> string body;
> } dbeWork;
>
> dbeBuild *dbeZeroBibs = NULL;
> dbeZeroBibs = new dbeBuild[2505]; // the errors are on this line

This is outside of any function. The above is a statement that has to be
inside of a function body.

> // error C2501: 'dbeZeroBibs' : missing storage-class or type specifiers
> // error C2040: 'dbeZeroBibs' : 'int' differs in levels of indirection
> from 'struct dbeBuild *'
[...]

--
Thomas
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