access violation problem

[JasBascom]

int main()
{
char record_typec = 'c';
record_typec = toupper(record_ typec);
* rec->Newcrecord.rec ord_type = record_typec;

etc
etc

\************** *************** *************** *\

I've run a debug on the program and this is where I'm encountering the access
violation problem. I've tried the dot operator to access the structure but that
doesn't appear to work. How can change the syntax and avoid the access
violation error?

[John Carson]

"JasBascom" <ja*******@aol. com> wrote in message
news:20******** *************** ****@mb-m11.aol.com

int main()
{
char record_typec = 'c';
record_typec = toupper(record_ typec);
* rec->Newcrecord.rec ord_type = record_typec;

etc
etc

\************** *************** *************** *\

I've run a debug on the program and this is where I'm encountering
the access violation problem. I've tried the dot operator to access
the structure but that doesn't appear to work. How can change the
syntax and avoid the access violation error?

Since most people here lack psychic abilities, I suggest that you tell us
how rec is defined.
--
John Carson
1. To reply to email address, remove donald
2. Don't reply to email address (post here instead)

[Rolf Magnus]

JasBascom wrote:

int main()
{
char record_typec = 'c';
record_typec = toupper(record_ typec);
* rec->Newcrecord.rec ord_type = record_typec;

etc
etc

\************** *************** *************** *\

I've run a debug on the program and this is where I'm encountering the
access violation problem. I've tried the dot operator to access the
structure but that doesn't appear to work. How can change the syntax
and avoid the access violation error?

How would anyone hwere know? What is rec? Where is it defined? It seems
to be a pointer, so where did you let it point to something? What is
the '*' at the beginning of the last line supposed to do?

[JasBascom]

rec is the pointer to a union
it is declared thus union Allrecords* rec.
Now that you know what rec is does that help you to help me?

[John Carson]

"JasBascom" <ja*******@aol. com> wrote in message
news:20******** *************** ****@mb-m11.aol.com

rec is the pointer to a union
it is declared thus union Allrecords* rec.
Now that you know what rec is does that help you to help me?

Yes. A pointer simply stores a memory address. Thus rec is meant to store
the address of an instance of Allrecords. However, you never create an
instance of Allrecords (as far as one can tell from the still-limited
information that you have provided), so rec never gets the chance to perform
its proper function. Instead, whatever value rec is storing points to memory
that you don't own and hence you get an access violation when you try to
write to it. You could create an instance of Allrecords with the following:

union Allrecords* rec = new Allrecords;

which allocates memory for an instance of Allrecords and makes rec point to
it. You could also forget about pointers and just declare:

union Allrecords rec_obj;

to create an Allrecords object called rec_obj.

Whether you are accessing the members of this structure correctly with

* rec->Newcrecord.rec ord_type = record_typec;

is again impossible to tell without seeing the definition of Allrecords.
--
John Carson
1. To reply to email address, remove donald
2. Don't reply to email address (post here instead)

[David Harmon]

On 20 Feb 2004 13:46:17 GMT in comp.lang.c++, ja*******@aol.c om
(JasBascom) was alleged to have written:

int main()
{
char record_typec = 'c';
record_typec = toupper(record_ typec);
* rec->Newcrecord.rec ord_type = record_typec;

etc

Variable "rec" is never declared above.
"Newrecord" is never declared above.
etc.

Post small, simplified but COMPLETE and COMPILEABLE samples so people
don't have to guess what you are talking about.

This issue is covered in Marshall Cline's C++ FAQ. See the topic
"[5.8] How do I post a question about code that doesn't work correctly?"
It is always good to check the FAQ before posting. You can get the FAQ
at:
http://www.parashift.com/c++-faq-lite/

[JasBascom]

The full program is follows. Thank you john for pointing out the access
violation error. i also have a problem with the declaring of an fstream object
- sort_file. For some reason my debugger is unable to move beyond that point in
the code.

I would also like to have rec.Newcrecord. record_type assigned the character 'c'
and to toupper the record_type. can you please help in both instances.

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>
#include <cstdlib>
using namespace std;

struct crecord {
char record_type;
char customercode[5];
char customername[21];
char customeraddress[61];
char customerbalance ;
char creditlimit;
int Totalbalance;
int Totalcreditlimi t;

};
struct irrecord {
char record_type;
char customercode[5];
char partnum[6];
char issue_rec[5];

};
struct drecord {
char record_type;
char customercode[5];
};
int loop = 200;
long offset = 1;

union Allrecords{
struct crecord Newcrecord;
struct irrecord Newirrecord;
struct drecord Newdrecord;

};
union Allrecords* rec;


void sort_function( union Allrecords* rec, fstream& validdata )
{

union Allrecords *str_ptr1, *str_ptr2, tempstr;
for(int i =0; i< loop; i++)
while( strcmp(str_ptr1[i].Newcrecord.cus tomercode, '\0') ||
strcmp(str_ptr1[i].Newdrecord.cus tomercode, '\0') ||
strcmp(str_ptr1[i].Newirrecord.cu stomercode, '\0'))
{
str_ptr2 = str_ptr1 + 1;//set to next element.

for( i=0; i<loop; i++)
while( strcmp(str_ptr2[i].Newcrecord.cus tomercode, '\0') ||
strcmp(str_ptr2[i].Newdrecord.cus tomercode, '\0'))
{
for(int i=0; i<loop; i++)
if( strcmp( str_ptr1[i].Newirrecord.cu stomercode,
str_ptr2[i].Newirrecord.cu stomercode + 1))
{
tempstr = *str_ptr1;
*str_ptr1 = *str_ptr2;
*str_ptr2 = tempstr;

}
*str_ptr1++;//incremented, so that the same code isn't sorted again
}
str_ptr2++;
}

}



int main()
{
const char sorted_file[] = "A:\\514650SDP2 .txt";
const char outfile[] = "A:\\514650VDP1 .bin";


long offset = 1;
int filesize;
int reccount;

fstream sort_file;
fstream validdata;

sort_file.open( "A:\\514650SDP2 .txt", ios::out);
if(!sort_file)
{
cout<<"Cannot create file"<< endl;
return EXIT_FAILURE;
};

validdata.open( "A:\\514650VDP1 .bin", ios::in || ios::binary);
if(!validdata)
{
cout<<" Cannot find file"<<endl;
return EXIT_FAILURE;
};
validdata.seekg (-offset, ios::end);
filesize = validdata.tellg ();
validdata.seekg (offset, ios::beg);

reccount = sizeof(filesize )/sizeof(Allrecor ds);
rec = new(Allrecords[reccount]);
validdata.read( (char*) rec, filesize);//read the whole file.

for(int i =0; i <reccount; i++)
{
switch(rec[i].Newdrecord.rec ord_type)
{
case 'c':
case 'C':
case 'i':
case 'I':
case 'r':
case 'R':
case 'd':
case 'D':
sort_function(r ec, validdata);
default:;
};

};

return 0;

}

[David Harmon]

On 20 Feb 2004 16:57:46 GMT in comp.lang.c++, ja*******@aol.c om
(JasBascom) was alleged to have written:

while( strcmp(str_ptr1[i].Newcrecord.cus tomercode, '\0') ||

Note that '\0', being a const integral expression with a value of zero,
is a valid C++ null pointer. But not what you wanted. What you wrote
is equivalent to

while( strcmp(str_ptr1[i].Newcrecord.cus tomercode, NULL) ||

while I think what you wanted is

while( strcmp(str_ptr1[i].Newcrecord.cus tomercode, "") ||

[David Harmon]

On 20 Feb 2004 16:57:46 GMT in comp.lang.c++, ja*******@aol.c om
(JasBascom) was alleged to have written:

validdata.open( "A:\\514650VDP1 .bin", ios::in || ios::binary);

Wrong, need bitwise or, not boolean or, should be

validdata.open( "A:\\514650VDP1 .bin", ios::in | ios::binary);

[David Harmon]

On 20 Feb 2004 16:57:46 GMT in comp.lang.c++, ja*******@aol.c om
(JasBascom) was alleged to have written:

for(int i=0; i<loop; i++)
if( strcmp( str_ptr1[i].Newirrecord.cu stomercode,
str_ptr2[i].Newirrecord.cu stomercode + 1))

{
OK, I give up on following the logic of your sort function. Especially
with all the comparison tests mixed in with the sort logic. How bad
would it hurt to replace it all with std::sort() ?

bool compare(const Allrecords* left, const Allrecords* right)
{
return strcmp( left->Newirrecord.cu stomercode,
right->Newirrecord.cu stomercode));
}

Then,

std::sort(rec, rec+reccount, compare);

This is probably not the exact right code because I gave up on exactly
following your logic, but how far off is it?