append output filename

[vj]

I am using Borland C++.

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

Thankyou

[tasneem.alsir]

vj wrote:

I am using Borland C++.

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

Thankyou

[tasneem.alsir]

vj wrote:

I am using Borland C++.

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

Thankyou

[SquareoftheHypotenuse]

Hi,

Try this....

FILE fp1;
char filename[30];

for(int i=0;i<10;i++)
{
......
......

sprintf(filenam e,"Voltage_N%d" ,i);
fp1 = fopen(filename, "w");

//Do all the 'Writing to the File' here..

fclose(fp1);
}

I guess this wud solve ur problem...

On May 24, 10:05 am, vj <vijayjany...@g mail.comwrote:

I am using Borland C++.

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

Thankyou

[Richard Heathfield]

SquareoftheHypo tenuse said:

Hi,

Try this....

FILE fp1;

Not what you meant.

char filename[30];

for(int i=0;i<10;i++)
{
.....
.....

sprintf(filenam e,"Voltage_N%d" ,i);
fp1 = fopen(filename, "w");

//Do all the 'Writing to the File' here..

Not till you checked that the fopen succeeded.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[vj]

On May 24, 11:49 am, SquareoftheHypo tenuse
<squareofthehyp oten...@gmail.c omwrote:

Hi,

Try this....

FILE fp1;
char filename[30];

for(int i=0;i<10;i++)
{
.....
.....

sprintf(filenam e,"Voltage_N%d" ,i);
fp1 = fopen(filename, "w");

//Do all the 'Writing to the File' here..

fclose(fp1);

}

I guess this wud solve ur problem...

On May 24, 10:05 am, vj <vijayjany...@g mail.comwrote:

I am using Borland C++.

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

Thankyou- Hide quoted text -

- Show quoted text -

Hi SquareoftheHypo tenuse
Thanks a lot to you (and all others who have shown interest) for a
nice reply.
It works amazingly, only thing is that initially I got an error, and
as prompted by the error message, I rectified it by using "FILE *fp1;"
instead of "FILE fp1;", and I am sure this is what you meant :)
For the time being, I just tested this bit of code to see if the
desired output files are generated (without actually writing any data
into those files). And the output files are generated as desired !
Could you please tell me what function (and its format) should I use
to write data to files (i.e. fprintf?). Because I normally use a
statement like "filename<<data 1<<data2<<endl; "
Thankyou

[R. Scott Mellow]

"vj" wrote

SquareoftheHypo tenuse wrote:

>Try this....

FILE fp1;
char filename[30];

for(int i=0;i<10;i++)
{
.....
.....

sprintf(filena me,"Voltage_N%d ",i);
fp1 = fopen(filename, "w");

//Do all the 'Writing to the File' here..

fclose(fp1);

}

It works amazingly, only thing is that initially I got an error, and
as prompted by the error message, I rectified it by using "FILE *fp1;"
instead of "FILE fp1;", and I am sure this is what you meant :)
For the time being, I just tested this bit of code to see if the
desired output files are generated (without actually writing any data
into those files). And the output files are generated as desired !
Could you please tell me what function (and its format) should I use
to write data to files (i.e. fprintf?). Because I normally use a
statement like "filename<<data 1<<data2<<endl; "

Here's my go:

#include <ostream>
#include <fstream>
#include <sstream>
#include <string>
#include <cstdlib>

using namespace std;

int main(int ac, char** av)
{
int n = 1;
int data1 = 14;
double data2 = 3.0;

if(ac 1)
n = strtol(av[1],NULL,10);

for(int i=0; i<n; ++i)
{

ostringstream oss;
oss << "Filename_N " << i + 1;
string fname(oss.str() );
ofstream fout(fname.c_st r());

if(fout)
{
fout << data1 << data2 << endl;
}
}

return 0;
}

--
Randy

[James Kanze]

On May 24, 7:05 am, vj <vijayjany...@g mail.comwrote:

I run a program which generates output data files, say 'Voltage.dat',
'Current.dat'. I have a variable in my code (say N), and for various
values of N (for each value of N), I generate these output data files.
After running the program once for a given value of N (say N equal to
1) and when the programme is finished, I manually append the generated
filename with the value of N, such as 'Voltage_N1.dat ',
'Current_N1.dat '. Then I go back to the code, make N=2, repeat the
procedure and append the generated output files with '_N2' etc.

Is there a simple way of appending the filenames automatically? In
other words, I want to run the programme in a loop for various values
of N (I know this bit i.e. how to make a loop:), and for each run, the
files generated (such as 'Voltage_N ') is appended by the value of N
i.e. 1, 2 and so on, followed by the extension '.dat'.
I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in C++.
(An easy to understand and basic reply with steps will be highly
appreciated).

std::ostringstr eam filename ;
filename << "Voltage_" << N << ".dat" ;
std::ofstream file( filename.str(). c_str() ) ;

Avoid the functions strcpy and strcat; they are not very safe.
If you are a beginner, it's much, much easier to use
std::string (and std::vector, instead of T[]). The iostream
functions are a bit more complicated, but still a great deal
easier and safer to use than the FILE* mess inherited from C.

--
James Kanze (GABI Software) email:ja******* **@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[Richard Heathfield]

James Kanze said:

On May 24, 7:05 am, vj <vijayjany...@g mail.comwrote:

<snip>

>I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in
C++.

<snip>

Avoid the functions strcpy and strcat; they are not very safe.

In C, strcpy and strcat are both perfectly safe if used correctly. Do
the C++ versions of these functions have different semantics or
interfaces? </rhetorical>

If you are a beginner, it's much, much easier to use
std::string (and std::vector, instead of T[]). The iostream
functions are a bit more complicated, but still a great deal
easier and safer to use than the FILE* mess inherited from C.

I can't agree that iostreams are easier to use than FILE *. I believe
that you believe it, but it is certainly a matter of opinion.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[James Kanze]

On May 25, 9:40 am, Richard Heathfield <[e-mail].i nvalidwrote:

James Kanze said:

On May 24, 7:05 am, vj <vijayjany...@g mail.comwrote:

<snip>

I know after reading the help file that there are functions like
strcpy and strcat, but couldn't figure out how to use them and their
exact format. Also, I am not conversant with Classes, pointers in
C++.

<snip>

Avoid the functions strcpy and strcat; they are not very safe.

In C, strcpy and strcat are both perfectly safe if used correctly.

Everything's perfectly safe "if used correctly". The question
is how difficult it is to use them correctly. Some functions,
like gets or sprintf, are impossible, or almost impossible to
use correctly. strcpy and strcat, while not as bad, require a
fair bit of care as well (and the C standard's committee has
proposed replacements, which are less dangerous). std::string
just works. Why use something that requires considerable care
and attention, when there is a simple solution which just works
available?

Do
the C++ versions of these functions have different semantics or
interfaces? </rhetorical>

C++ supports the C interfaces for reasons of C compatibility.
In C++, however, the type of a string is std::string, not
char[], and the functionality is supported with the = and the +=
operators. The result is something that is both easier to
write, and safer.

If you are a beginner, it's much, much easier to use
std::string (and std::vector, instead of T[]). The iostream
functions are a bit more complicated, but still a great deal
easier and safer to use than the FILE* mess inherited from C.

I can't agree that iostreams are easier to use than FILE *. I believe
that you believe it, but it is certainly a matter of opinion.

If the goal is a core dump, then printf is definitely easier
than anything in iostreams. But for anything useful, iostream's
beats FILE* hands down. How do you output a user defined type
using printf? How do you output to a socket? How do you read
skipping comments, or write putting a time stamp at the
beginning of each line?

In the end, FILE* isn't really even usable.

--
James Kanze (GABI Software) email:ja******* **@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]