Access violation error

M

muser

In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is.


#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>
#include <cstdlib>


using namespace std;

struct crecord {
long customercode[5];
char customername[21];
char customeraddress[61];
double customerbalance;
double creditlimit;

};
crecord Newcrecord;

struct irrecord {
long customercode[5];
long partnum[5];
long issue_rec;

};
irrecord Newirrecord;

struct drecord {
long customercode[5];
};
drecord Newdrecord;






////////////////////////////////////////////////////////////
bool IRRecordvalidlength(char* record)
{
int len;

switch(record[0])
{
case'i':
case'I':
case'r':
case'R':

len= strlen(record);
if(len<17)
return false;
break;


}

return true;
};
////////////////////////////////////////////////////////////
bool CRecordvalidlength(char* record)
{
int len;

switch(record[0])
{
case'c':
case'C':

len = strlen(record);
if(len<103)
return false;
break;

}


return true;

}
////////////////////////////////////////////////////////
bool Drecordvalidlength( char* record )
{
int len;

switch(record[0])
{
case'd':
case'D':

len = strlen(record);
if(len<7)
return false;
break;

}
return true;
}
////////////////////////////////////////////////////////////////////////////
bool CheckAllNumeric( const char * string )
{
int Len = strlen( string );

for( int i = 0; i < Len; ++i )
if( !isdigit( string ) )
return false;

return true;
}

////////////////////////////////////////////////////////////////////////////
bool CheckFloatNumber( const char* string )
{
int Len = strlen( string );

for( int i = 0; i < Len; ++i )
if( !isdigit( string ) &&
string != '.' )
return false;

return true;
}

///////////////////////////////////////////////////////////////////////////
irrecord* CheckDigit(ofstream& prnfile, ofstream& validdata, char*
record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 6);
code[5] = '\0';
Newirrecord.customercode[5] = atol( code );


for(int i =0; i < 6; ++i)
check1 += Newirrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(! Newirrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

if(Newirrecord.customercode[5] == checkdigit){

validdata.write((char*) record, Newirrecord.customercode[5]);
}

}
/////////////////////////////////////////////////////////////////////////////////////

drecord* checkdigit(ofstream& prnfile, ofstream& validdata, char*
record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 5);
code[5] = '\0';
Newdrecord.customercode[5] = atol( code );


for(int i =0; i < 4; ++i)
check1 += Newdrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(! Newdrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newdrecord.customercode[5]);


}
////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////
crecord* checkdigitforcustomercode( ofstream& prnfile, ofstream&
validdata, char* record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 5);
code[5] = '\0';
Newcrecord.customercode[5] = atol( code );


for(int i =0; i < 6; ++i)
check1 += Newcrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(checkdigit == 11){
checkdigit = 'X';
}
else
if(checkdigit = checkdigit = 10){
checkdigit = '0';
}


if(! Newcrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newcrecord.customercode[5]);

}
////////////////////////////////////////////////////////////////////////////////////
irrecord* checkdigitforpartnum(ofstream& prnfile, ofstream& validdata,
char* record)
{
int weightingfactor2;
char part_num[6];
int partnumcheck;
int produce;
int holdall;

strncpy(part_num, &record[7], 6);
part_num[6] = '\0';
Newirrecord.partnum[6] = atol( part_num );

weightingfactor2 = 6;

for(int i=0; i < 6; ++i)
holdall += Newirrecord.partnum * weightingfactor2;
weightingfactor2 --;

produce = holdall % 11;

partnumcheck = 11 - produce;


if(partnumcheck == 11){
partnumcheck = 'X';
}
else
if(partnumcheck = 10){
partnumcheck = '0';
}

if(! Newirrecord.partnum[5] == partnumcheck){
prnfile<< "Invalid: Incorrect part number, check digit invalid";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newirrecord.partnum[5]);

}

////////////////////////////////////////////////////////////////////////////////////
bool CheckAddress( const char* alpha )
{

int max_alpha = 60;

for( int i = 0; i < max_alpha; ++i )
if( !isalpha( alpha ) && ( alpha != ';;;;' ) && ( alpha !=
' ' ))
if(Newcrecord.customeraddress[61] != (alpha))
return false;

return true;


}
///////////////////////////////////////////////////////////////////////////////


bool Processcrecord( ofstream& prnfile, ofstream& validdata, char*
record )
{
char customercode[6];
char balance[10];
char limit[10];


crecord Newcrecord;

//
// process the customer code
//
strncpy( customercode, &record[1], 5 );
customercode[5] = '\0';
if( !CheckAllNumeric( customercode ) ) {
prnfile << "Invalid: customer code needs to be all numeric
[position 3 - 5 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.customercode[5] = atol( customercode );

//
// process the customer name
//
strncpy( Newcrecord.customername, &record[7], 20 );
Newcrecord.customername[20] = '\0';

//
// process the customer address
//
strncpy( Newcrecord.customeraddress, &record[27], 61 );
Newcrecord.customeraddress[61] = '\0';




// process the customer balance
//
strncpy( balance, &record[87], 9 );
balance[9] = '\0';
if( !CheckFloatNumber( balance ) ) {
prnfile << "Invalid: balance field is not a valid number [position
88 - 9 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.customerbalance = atof( balance );


validdata.write((char*) record, Newcrecord.customerbalance );

//
// process the customer limit
//
strncpy( limit, &record[97], 9 );
limit[9] = '\0';
if( !CheckFloatNumber( limit ) ) {
prnfile << "Invalid: limit field is not a valid number [position
98 - 9 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.creditlimit = atof( limit );

validdata.write((char*) record, Newcrecord.creditlimit );

return true;

}

///////////////////////////////////////////////////////

bool processdrecord( char* record, ofstream& prnfile, ofstream&
validdata )
{
drecord Newdrecord;
char customercode[5];

strncpy( customercode, &record[1], 5);
customercode[5] = '\0';
if(!CheckAllNumeric( customercode )){
prnfile<< "Invalid: D record customer code does not contain
numerical format";
prnfile<< record <<endl;
return false;
}
Newdrecord.customercode[5] = atol( customercode );

validdata.write((char*) record, Newdrecord.customercode[5] );


return true;
}

/////////////////////////////////////////////////////////////////////////
bool ProcessIRecord( ofstream& prnfile, ofstream& validdata, char*
record )
{


char customer[6];
char issue_rec[5];
char part[6];

long customer_code;
long issuerec;
long partnum[6];



//
// process the customer code
//
strncpy( customer, &record[2], 5 );
customer[6] = '\0';
if( !CheckAllNumeric( customer ) ) {
prnfile << "Invalid: customer code needs to be all numeric
[position 3 - 5 characters]:\n";
prnfile << record << endl;
return false;
}
customer_code = atol( customer );

//
// process the part number
//
strncpy( part, &record[7], 6 );
part[6] = '\0';
if( !CheckAllNumeric( part ) ) {
prnfile << "Invalid: part number needs to be all numeric [position
9 - 6 characters]:\n";
prnfile << record << endl;
return false;
}
partnum[6] = atol( part );

validdata.write((char*) record, partnum[6]);

return true;

//
// process the third number
//
strncpy( issue_rec, &record[13], 5 );
issue_rec[5] = '\0';
if( !CheckAllNumeric( issue_rec ) ) {
prnfile << "Invalid: the code needs to be all numeric [position 16
- 4 characters]:\n";
prnfile << record << endl;
return false;
}
issuerec = atol( issue_rec );


return true;
}

/////////////////////////////////////////////////////////////////////////


int main()
{
const char infile[] = "A:\\514650TD.txt";
const char outfile[] = "A:\\514650VD.DAT";
const char printerfile[] = "A:\\514650.TXT";

int max = 256;

char temp1[256];



ifstream testdata;
ofstream prnfile;
ofstream validdata;

testdata.open("A:\\514650TD.txt", ios::in);
if(!testdata)
{
cout<<"The file does not already exist" << infile << endl;
return EXIT_FAILURE;
}

validdata.open("A:\\514650.DAT", ios::eek:ut | ios::binary);
if(!validdata.is_open())
{
cout<<" The file could not be opened " << outfile <<endl;
return EXIT_FAILURE;
}

prnfile.open("A:\\514650.TXT", ios::eek:ut);
if(!prnfile)
{
cout<< "File could not be opened" << prnfile << endl;
return EXIT_FAILURE;
};


prnfile << "C_RECORD, I-R RECORD, D_RECORD ERRORS" << endl;

while( testdata.getline( temp1, sizeof(temp1)) ){
if(!CRecordvalidlength( temp1 )){
prnfile<<"Invalid: record does not contain enough characters:\n";
prnfile<< temp1 <<endl;
continue;
}
if(!IRRecordvalidlength( temp1 )){
prnfile<< "Invalid: record does not contain enough characters:\n";
prnfile<< temp1 << endl;
continue;
}
if(!Drecordvalidlength( temp1 )){
prnfile<< "Invalid: record does not contain enough characters:\n";
prnfile<< temp1 << endl;
continue;
};

switch( temp1[0] )
{
case 'c':
case 'C':
Processcrecord( prnfile, validdata, temp1 );
checkdigitforcustomercode( prnfile, validdata, temp1);
break;

case 'i':
case 'I':
case 'r':
case 'R':
ProcessIRecord( prnfile, validdata, temp1 );
CheckDigit( prnfile, validdata, temp1 );
checkdigitforpartnum( prnfile, validdata, temp1 );
break;

case 'd':
case 'D':
processdrecord( temp1, prnfile, validdata );
checkdigit( prnfile, validdata, temp1 );
break;
default: prnfile<< "Unknown record";
prnfile<< temp1 << endl;
};

}
testdata.close();
validdata.close();
prnfile.close();


return EXIT_SUCCESS;

};
 
A

Artie Gold

muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is.
Click to expand...

I'm not going to go through your code line by line, but at least a
couple of things jump right out. See below:
#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>
#include <cstdlib>


using namespace std;

struct crecord {
long customercode[5];
char customername[21];
char customeraddress[61];
double customerbalance;
double creditlimit;

};
crecord Newcrecord;

struct irrecord {
long customercode[5];
long partnum[5];
long issue_rec;

};
irrecord Newirrecord;

struct drecord {
long customercode[5];
};
drecord Newdrecord;






////////////////////////////////////////////////////////////
bool IRRecordvalidlength(char* record)
{
int len;

switch(record[0])
{
case'i':
case'I':
case'r':
case'R':

len= strlen(record);
if(len<17)
return false;
break;


}

return true;
};
////////////////////////////////////////////////////////////
bool CRecordvalidlength(char* record)
{
int len;

switch(record[0])
{
case'c':
case'C':

len = strlen(record);
if(len<103)
return false;
break;

}


return true;

}
////////////////////////////////////////////////////////
bool Drecordvalidlength( char* record )
{
int len;

switch(record[0])
{
case'd':
case'D':

len = strlen(record);
if(len<7)
return false;
break;

}
return true;
}
////////////////////////////////////////////////////////////////////////////
bool CheckAllNumeric( const char * string )
{
int Len = strlen( string );

for( int i = 0; i < Len; ++i )
if( !isdigit( string ) )
return false;

return true;
}

////////////////////////////////////////////////////////////////////////////
bool CheckFloatNumber( const char* string )
{
int Len = strlen( string );

for( int i = 0; i < Len; ++i )
if( !isdigit( string ) &&
string != '.' )
return false;

return true;
}

///////////////////////////////////////////////////////////////////////////
irrecord* CheckDigit(ofstream& prnfile, ofstream& validdata, char*
record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 6);
Click to expand...


Your copying 6 `char's into an array of length 5.
code[5] = '\0';
Click to expand...

No, `code[5]' does not exist. The last element in the array is
`code[4]' (arrays in C++ are zero-based, hence valid indices run
from 0 to 4).
Newirrecord.customercode[5] = atol( code );


for(int i =0; i < 6; ++i)
check1 += Newirrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(! Newirrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

if(Newirrecord.customercode[5] == checkdigit){

validdata.write((char*) record, Newirrecord.customercode[5]);
}

}
/////////////////////////////////////////////////////////////////////////////////////

drecord* checkdigit(ofstream& prnfile, ofstream& validdata, char*
record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 5);
code[5] = '\0';
Click to expand...


Similarly, see above.
Newdrecord.customercode[5] = atol( code );


for(int i =0; i < 4; ++i)
check1 += Newdrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(! Newdrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newdrecord.customercode[5]);


}
////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////
crecord* checkdigitforcustomercode( ofstream& prnfile, ofstream&
validdata, char* record )
{
char code[5];
int weightingfactor = 5;
int checkdigit;
int remainder;
int check1;

strncpy(code, &record[2], 5);
code[5] = '\0';
Newcrecord.customercode[5] = atol( code );


for(int i =0; i < 6; ++i)
check1 += Newcrecord.customercode * weightingfactor;
weightingfactor --;

remainder = check1 % 11;

checkdigit = 11 - remainder;

if(checkdigit == 11){
checkdigit = 'X';
}
else
if(checkdigit = checkdigit = 10){
checkdigit = '0';
}


if(! Newcrecord.customercode[5] == checkdigit){
prnfile<< "Invalid customer number";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newcrecord.customercode[5]);

}
////////////////////////////////////////////////////////////////////////////////////
irrecord* checkdigitforpartnum(ofstream& prnfile, ofstream& validdata,
char* record)
{
int weightingfactor2;
char part_num[6];
int partnumcheck;
int produce;
int holdall;

strncpy(part_num, &record[7], 6);
part_num[6] = '\0';
Newirrecord.partnum[6] = atol( part_num );

weightingfactor2 = 6;

for(int i=0; i < 6; ++i)
holdall += Newirrecord.partnum * weightingfactor2;
weightingfactor2 --;

produce = holdall % 11;

partnumcheck = 11 - produce;


if(partnumcheck == 11){
partnumcheck = 'X';
}
else
if(partnumcheck = 10){
partnumcheck = '0';
}

if(! Newirrecord.partnum[5] == partnumcheck){
prnfile<< "Invalid: Incorrect part number, check digit invalid";
prnfile<< record << endl;
}
return false;

validdata.write((char*) record, Newirrecord.partnum[5]);

}

////////////////////////////////////////////////////////////////////////////////////
bool CheckAddress( const char* alpha )
{

int max_alpha = 60;

for( int i = 0; i < max_alpha; ++i )
if( !isalpha( alpha ) && ( alpha != ';;;;' ) && ( alpha !=
' ' ))
if(Newcrecord.customeraddress[61] != (alpha))
return false;

return true;


}
///////////////////////////////////////////////////////////////////////////////


bool Processcrecord( ofstream& prnfile, ofstream& validdata, char*
record )
{
char customercode[6];
char balance[10];
char limit[10];


crecord Newcrecord;

//
// process the customer code
//
strncpy( customercode, &record[1], 5 );
customercode[5] = '\0';
if( !CheckAllNumeric( customercode ) ) {
prnfile << "Invalid: customer code needs to be all numeric
[position 3 - 5 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.customercode[5] = atol( customercode );

//
// process the customer name
//
strncpy( Newcrecord.customername, &record[7], 20 );
Newcrecord.customername[20] = '\0';

//
// process the customer address
//
strncpy( Newcrecord.customeraddress, &record[27], 61 );
Newcrecord.customeraddress[61] = '\0';




// process the customer balance
//
strncpy( balance, &record[87], 9 );
balance[9] = '\0';
if( !CheckFloatNumber( balance ) ) {
prnfile << "Invalid: balance field is not a valid number [position
88 - 9 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.customerbalance = atof( balance );


validdata.write((char*) record, Newcrecord.customerbalance );

//
// process the customer limit
//
strncpy( limit, &record[97], 9 );
limit[9] = '\0';
if( !CheckFloatNumber( limit ) ) {
prnfile << "Invalid: limit field is not a valid number [position
98 - 9 characters]:\n";
prnfile << record << endl;
return false;
}
Newcrecord.creditlimit = atof( limit );

validdata.write((char*) record, Newcrecord.creditlimit );

return true;

}

///////////////////////////////////////////////////////

bool processdrecord( char* record, ofstream& prnfile, ofstream&
validdata )
{
drecord Newdrecord;
char customercode[5];

strncpy( customercode, &record[1], 5);
customercode[5] = '\0';
if(!CheckAllNumeric( customercode )){
prnfile<< "Invalid: D record customer code does not contain
numerical format";
prnfile<< record <<endl;
return false;
}
Newdrecord.customercode[5] = atol( customercode );

validdata.write((char*) record, Newdrecord.customercode[5] );


return true;
}

/////////////////////////////////////////////////////////////////////////
bool ProcessIRecord( ofstream& prnfile, ofstream& validdata, char*
record )
{


char customer[6];
char issue_rec[5];
char part[6];

long customer_code;
long issuerec;
long partnum[6];



//
// process the customer code
//
strncpy( customer, &record[2], 5 );
customer[6] = '\0';
if( !CheckAllNumeric( customer ) ) {
prnfile << "Invalid: customer code needs to be all numeric
[position 3 - 5 characters]:\n";
prnfile << record << endl;
return false;
}
customer_code = atol( customer );

//
// process the part number
//
strncpy( part, &record[7], 6 );
part[6] = '\0';
if( !CheckAllNumeric( part ) ) {
prnfile << "Invalid: part number needs to be all numeric [position
9 - 6 characters]:\n";
prnfile << record << endl;
return false;
}
partnum[6] = atol( part );

validdata.write((char*) record, partnum[6]);

return true;

//
// process the third number
//
strncpy( issue_rec, &record[13], 5 );
issue_rec[5] = '\0';
if( !CheckAllNumeric( issue_rec ) ) {
prnfile << "Invalid: the code needs to be all numeric [position 16
- 4 characters]:\n";
prnfile << record << endl;
return false;
}
issuerec = atol( issue_rec );


return true;
}

/////////////////////////////////////////////////////////////////////////


int main()
{
const char infile[] = "A:\\514650TD.txt";
const char outfile[] = "A:\\514650VD.DAT";
const char printerfile[] = "A:\\514650.TXT";

int max = 256;

char temp1[256];



ifstream testdata;
ofstream prnfile;
ofstream validdata;

testdata.open("A:\\514650TD.txt", ios::in);
if(!testdata)
{
cout<<"The file does not already exist" << infile << endl;
return EXIT_FAILURE;
}

validdata.open("A:\\514650.DAT", ios::eek:ut | ios::binary);
if(!validdata.is_open())
{
cout<<" The file could not be opened " << outfile <<endl;
return EXIT_FAILURE;
}

prnfile.open("A:\\514650.TXT", ios::eek:ut);
if(!prnfile)
{
cout<< "File could not be opened" << prnfile << endl;
return EXIT_FAILURE;
};


prnfile << "C_RECORD, I-R RECORD, D_RECORD ERRORS" << endl;

while( testdata.getline( temp1, sizeof(temp1)) ){
if(!CRecordvalidlength( temp1 )){
prnfile<<"Invalid: record does not contain enough characters:\n";
prnfile<< temp1 <<endl;
continue;
}
if(!IRRecordvalidlength( temp1 )){
prnfile<< "Invalid: record does not contain enough characters:\n";
prnfile<< temp1 << endl;
continue;
}
if(!Drecordvalidlength( temp1 )){
prnfile<< "Invalid: record does not contain enough characters:\n";
prnfile<< temp1 << endl;
continue;
};

switch( temp1[0] )
{
case 'c':
case 'C':
Processcrecord( prnfile, validdata, temp1 );
checkdigitforcustomercode( prnfile, validdata, temp1);
break;

case 'i':
case 'I':
case 'r':
case 'R':
ProcessIRecord( prnfile, validdata, temp1 );
CheckDigit( prnfile, validdata, temp1 );
checkdigitforpartnum( prnfile, validdata, temp1 );
break;

case 'd':
case 'D':
processdrecord( temp1, prnfile, validdata );
checkdigit( prnfile, validdata, temp1 );
break;
default: prnfile<< "Unknown record";
prnfile<< temp1 << endl;
};

}
testdata.close();
validdata.close();
prnfile.close();


return EXIT_SUCCESS;

};
Click to expand...


The items noted above are sufficient to produce undefined behavior
-- after which all bets are off.

Also, in the future, pare down your code to the smallest possible
compilable snippet *before* you post; in doing so, you will often
find the error yourself!

HTH,
--ag
 
K

Kevin Saff

muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is
Click to expand...
[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
 
M

muser

Kevin Saff said:
muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is
Click to expand...
[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

Kevin, doesn't my code[5] contain a NULL character and isn't that
housed in the fifth element?
 
R

Ron Natalie

muser said:
You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

Kevin, doesn't my code[5] contain a NULL character and isn't that
housed in the fifth element?
Click to expand...

No, code[5] refers to the sixth element.

code[0] is the first, code[1] is the scond, code[2] is the third, code[3] is the forth,
code[4] is the fifth.

These are the only locations you are allowed to access.

code[5] is one past the end of the allocation. You touch it, you can't count
on any specific behavior.
 
J

James Lothian

muser said:
Kevin Saff said:
muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is
Click to expand...
[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

Kevin, doesn't my code[5] contain a NULL character and isn't that
housed in the fifth element?
Click to expand...

code[5] is the *sixth* element. char code[5] declares an array of five
elements, numbered 0 to 4.

James
 
M

muser

Kevin Saff said:
muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is
Click to expand...
[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

sorry kevin, posted my reply moments after getting up, disregard my
reply, and thank you for the advance.
 
A

Adam Fineman

Simon said:
Kevin Saff said:
You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!
Click to expand...


I'm a bit surprised that the OP's compiler didn't issue a warning on
this.
Click to expand...

I'd be very surprised if any compiler did, actually.

- Adam
 
F

Frank Schmitt

Adam Fineman said:
Simon said:
Kevin Saff said:
You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!
Click to expand...
I'm a bit surprised that the OP's compiler didn't issue a warning on
this.
Click to expand...

I'd be very surprised if any compiler did, actually.
Click to expand...

Be surprised, then :)

$icc -w2 compilertest.cpp
compilertest.cpp(3): warning #175: subscript out of range
code[5] = '\0';

$icc -V
Intel(R) C++ Compiler for 32-bit applications, Version 7.0 Build 20030212Z
Copyright (C) 1985-2003 Intel Corporation. All rights reserved.

kind regards
frank
 
M

muser

Kevin Saff said:
muser said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is
Click to expand...
[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

sorry kevin, posted my reply moments after getting up, disregard my
reply, and thank you for the advance.
Click to expand...

Sorry to return to this thread, but when I made my character array
char code[6]
and put the code, code[6] = '\0';
my compiler kept picking up something it shouldn't.
I'm feeding this line into the array c12345stevelaw. the numbers is
all I want to appear in the array, but when I check that code only
contains numbers it produces an error. the char code[6] isn't assigned
to the string terminator but to the 's' in steve. I've gone back to
using char code[5] and it works perfectly. But I did that last time
which caused an error after running the program a few times. why is
char code[6] not being assigned the string terminator, even though the
code explicitly implies this?
 
L

lilburne

muser said:
Kevin Saff said:
In the code I supplied before this one, the cause of the problem is an
access violation error. When I run the debugger it skips into what I
can only assume is the compilers version of my code. And I don't know
where the problem lies in the code. Can anyone run it through there
own compiler please and tell me where and what the problem is

[SNIP WAY TOO MUCH INFORMATION]

If you read the replies to your earlier post, you will see your problem.
Maybe your news server is slow - even then try to keep posts about the same
problem in the same thread; wait at least a day or two to see if your post
went through.

You frequently write past the end of an array, as in:

char code[5]; // has 5 chars, numbered _0_ to _4_
code[5] = '\0'; // you are writing to char _5_ which does not exist!

Don't do this.
Click to expand...

sorry kevin, posted my reply moments after getting up, disregard my
reply, and thank you for the advance.
Click to expand...


Sorry to return to this thread, but when I made my character array
char code[6]
and put the code, code[6] = '\0';
my compiler kept picking up something it shouldn't.
I'm feeding this line into the array c12345stevelaw. the numbers is
all I want to appear in the array, but when I check that code only
contains numbers it produces an error. the char code[6] isn't assigned
to the string terminator but to the 's' in steve. I've gone back to
using char code[5] and it works perfectly. But I did that last time
which caused an error after running the program a few times. why is
char code[6] not being assigned the string terminator, even though the
code explicitly implies this?
Click to expand...

Its because you are using the wrong language try fortran.
 

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