read and write columns

[Bill Cunningham]

I don't think I can do this without some help or hints. Here is the code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;
double mean=0,linput=0 ;
FILE *fpr, *fpw;
mean=input+linp ut/count;
if ((fpw=fopen("da ta","w"))!=EOF) ;
if ((fpr=fopen("da ta","r"))!=EOF) ;
if ((fscanf(fpr,in put,linput,mean ))==0;
fprintf(fpw,"%d \t%d\t%d\n",inp ut,input+linput ,mean);
}

It's very much incomplete. I have two stream open one for reading and one
for writing but the count that I have been speaking of, I don't know how to
increment it.

Bill

[Richard Heathfield]

Bill Cunningham said:

I don't think I can do this without some help or hints. Here is the
code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;

div is a standard C library function prototyped in <stdlib.h>, so this
definition of div "shadows" that function, preventing you from using it.
It is best to avoid using standard C library function names except when
referring to standard C library functions.

double mean=0,linput=0 ;
FILE *fpr, *fpw;
mean=input+linp ut/count;
if ((fpw=fopen("da ta","w"))!=EOF) ;

You have K&R2. Look up fopen's return value on failure. You've been told
about this before, and quite recently too.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Barry Schwarz]

On Thu, 03 Jul 2008 00:12:03 GMT, "Bill Cunningham" <no****@nspam.c om>
wrote:

I don't think I can do this without some help or hints. Here is the code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;

White space is free. Use it make your code readable.

double mean=0,linput=0 ;
FILE *fpr, *fpw;
mean=input+linp ut/count;

What is the value of count? Are you allowed to divide by that value?

if ((fpw=fopen("da ta","w"))!=EOF) ;

Didn't your compiler generate a diagnostic here? What type and range
of EOF? What type of value does fopen return to be stored in fpw? Are
the two in any way compatible.

if ((fpr=fopen("da ta","r"))!=EOF) ;
if ((fscanf(fpr,in put,linput,mean ))==0;

You couldn't figure out that you are missing a right parenthesis here?
What do you expect that superfluous semicolon to do?

What are the arguments to fscanf supposed to be? Other than fpr, do
any of yours meet the criteria?

Admit it, you didn't even try to compile the code.

fprintf(fpw,"%d \t%d\t%d\n",inp ut,input+linput ,mean);
}

What type of argument does %d promise? What are the types of your
arguments.

>
It's very much incomplete. I have two stream open one for reading and one
for writing but the count that I have been speaking of, I don't know how to
increment it.

If you don't know how to increment count, you need to start with
programs that are very much more basic than this. Strange that you
didn't have any trouble incrementing input above. OK, so you did have
trouble but at least you knew (lucky guess?) which operator to use.


Remove del for email
** Posted from http://www.teranews.com **

[rahul]

On Jul 3, 5:12 am, "Bill Cunningham" <nos...@nspam.c omwrote:

I don't think I can do this without some help or hints. Here is the code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;
double mean=0,linput=0 ;
FILE *fpr, *fpw;

mean=input+linp ut/count;

What exactly do you mean? input + (linput / count) or (input +
linput) / count. Do you see a divide by zero problem here? Since input
and linput are define as double, your mean equals infinity.

if ((fpw=fopen("da ta","w"))!=EOF) ;
if ((fpr=fopen("da ta","r"))!=EOF) ;

May be next time you should remember fopen returns FILE * and the
error checking is done against NULL.
So if ((fpw = fopen("data", "w")) != NULL);
But heck; even now it is meaning-less(that ;, if you didn't notice).
Check for NULL and then do nothing - just proceed with the code.

if ((fscanf(fpr,in put,linput,mean ))==0;

Again, check for error and do nothing. And this won't compile on any
known compiler(missin g parenthesis).

fprintf(fpw,"%d \t%d\t%d\n",inp ut,input+linput ,mean);
}

input, input + linput are doubles. mean is a double and equals
infinity. %d, if you have a look at the doc, is meant for signed
integers.

It's very much incomplete. I have two stream open one for reading and one
for writing but the count that I have been speaking of, I don't know how to
increment it.

I don't know but it looks like to me that you created this mess on
purpose. There are better ways to have fun if that is what you are
trying to have over here.

[Richard Heathfield]

Barry Schwarz said:

On Thu, 03 Jul 2008 00:12:03 GMT, "Bill Cunningham" <no****@nspam.c om>
wrote:

> I don't think I can do this without some help or hints. Here is the
code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;

White space is free. Use it make your code readable.

> double mean=0,linput=0 ;
FILE *fpr, *fpw;
mean=input+linp ut/count;

What is the value of count? Are you allowed to divide by that value?

Good spot, Barry. I missed that completely.

> if ((fpw=fopen("da ta","w"))!=EOF) ;

Didn't your compiler generate a diagnostic here?

Just a thought here - Bill Cunningham is a self-confessed slow learner, so
it might be quicker for us and more productive for him if we just point
out the *first* mistake. Maybe over time BC will begin to understand that
he's not going to get help with problem B for so long as his code
continues to exhibit problem A, and he might - just *might* - work out
that eliminating problem A from all his code is therefore a productive
thing for him to do.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[rahul]

On Jul 3, 5:12 am, "Bill Cunningham" <nos...@nspam.c omwrote:

I don't think I can do this without some help or hints. Here is the code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {

Though it is legal, naming the parameter the same as your function
name is not a good practice.

[Ron Ford]

On Thu, 03 Jul 2008 04:57:37 +0000, Richard Heathfield posted:

Barry Schwarz said:

>On Thu, 03 Jul 2008 00:12:03 GMT, "Bill Cunningham" <no****@nspam.c om>
wrote:

>> I don't think I can do this without some help or hints. Here is the
code
I have.

#include <stdio.h>
#include <stdlib.h>

double input(double input) {
int count=0,div=0;

White space is free. Use it make your code readable.

>> double mean=0,linput=0 ;
FILE *fpr, *fpw;
mean=input+linp ut/count;

What is the value of count? Are you allowed to divide by that value?

Good spot, Barry. I missed that completely.

>> if ((fpw=fopen("da ta","w"))!=EOF) ;

Didn't your compiler generate a diagnostic here?

Just a thought here - Bill Cunningham is a self-confessed slow learner, so
it might be quicker for us and more productive for him if we just point
out the *first* mistake. Maybe over time BC will begin to understand that
he's not going to get help with problem B for so long as his code
continues to exhibit problem A, and he might - just *might* - work out
that eliminating problem A from all his code is therefore a productive
thing for him to do.

I think this idiom is largely unnecessary:

>> if ((fpw=fopen("da ta","w"))!=EOF) ;

If every char you put has to be tested for EOF, then you have a deficient
OS. I gave windows 40 gigs today. It prompts me annoyingly for lack of
hog space.

That the C programming language must be constarined to the average clicker
is a distortion.
--
Ron Ford

[Richard Heathfield]

Ron Ford said:

<snip>

>

I think this idiom is largely unnecessary:

>>> if ((fpw=fopen("da ta","w"))!=EOF) ;

It isn't an idiom. It's just a bug.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Ron Ford]

On Thu, 03 Jul 2008 09:27:48 +0000, Richard Heathfield posted:

Ron Ford said:

<snip>

>>

I think this idiom is largely unnecessary:

>>>> if ((fpw=fopen("da ta","w"))!=EOF) ;

It isn't an idiom. It's just a bug.

When I have to do IO with C, I use safegets, but I don't think that that is
what you mean.

My point was that my OS doesn't say nay to me on a char basis.

I'm curious what you mean.
--
Ron Ford
"Close enough to Texas to feel disinformation. "

[Richard Heathfield]

Ron Ford said:

On Thu, 03 Jul 2008 09:27:48 +0000, Richard Heathfield posted:

>Ron Ford said:

<snip>

>>>

I think this idiom is largely unnecessary:

> if ((fpw=fopen("da ta","w"))!=EOF) ;

It isn't an idiom. It's just a bug.

When I have to do IO with C, I use safegets, but I don't think that that
is what you mean.

My point was that my OS doesn't say nay to me on a char basis.

I'm curious what you mean.

The fopen function never returns EOF, ever. Since EOF is an int, and since
fopen returns a FILE *, testing the return value of fopen against EOF is
completely pointless. (In this case, the semicolon makes it doubly
pointless.)

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999