Redirecting input from file

[dmoran21@cox.net]

Re: Redirecting input from file

On Jul 4, 9:19 am, Richard Heathfield <r...@see.sig.i nvalidwrote:

dmora...@cox.ne t said:
>
<snip>
>

I got my hands on the error messages that I got (I got into my e-mail
at work, but since I'm not in the office today, I can't get to my
code). I got the following:

>

Cannot convert 'void*' to 'float*' in function main(int, char * *)

>
Either:
>
(a) you forgot to #include <stdlib.hNope , Included it.
(b) you're using C++ Possibly, but don't think so.
>
if (a), include it.
if (b), either
>
(d) you're using C++ deliberately Don't think so
(e) you're using C++ accidentally Possibly
>
if (d), ask in comp.lang.c++ rather than comp.lang.c
if (e), you may find that changing your filename suffix from .cpp to .c
is sufficient.
>
--
Richard Heathfield <http://www.cpax.org.uk >
Email: -www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

I won't reply again until I can get to my code. There's really nothing
I can do or share until then.

Dave

[dmoran21@cox.net]

Re: Redirecting input from file

>
This is a very strong indication that you are using a C++ compiler and
not a C compiler.

That's a good possibility...I 'll have to check the compiler.

Dave

[Flash Gordon]

Re: Redirecting input from file

dmoran21@cox.ne t wrote, On 04/07/07 14:50:

On Jul 4, 8:08 am, Richard Heathfield <r...@see.sig.i nvalidwrote:

<snip>

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

Please do not quote peoples signatures, the bit generally after a "-- ".
In fact, trim anything not relevant to your reply as I have done.

I got my hands on the error messages that I got (I got into my e-mail
at work, but since I'm not in the office today, I can't get to my
code). I got the following:
>
Cannot convert 'void*' to 'float*' in function main(int, char * *)

That probably means you are compiling your code as C++ rather than C. To
find out how to drive the tools you are using ask in a group dedicated
to your tools or system, but common reasons are using an upper case C as
the extension instead of a lower case c, using the extension .cpp, or
having a switch set somewhere to say it is C++. C++ is a significantly
different language.

I will post my code tomorrow when I'm in the office.

Include information about whatever your symptoms are when you do, most
people don't attempt to remember the problems that are being discussed
in all the threads. Oh, and make sure you compile as C instead of C++
before posting anything else.
--
Flash Gordon

[CBFalconer]

Re: Redirecting input from file

Richard Heathfield wrote:

>

.... snip ...

>
Drop all those silly casts. If that gives you diagnostic messages
at compile time or breaks the behaviour at runtime, *tell us*, and
we'll show you how to fix it. 99.9908237% of the time, casts
aren't the right fix. ^^^^^^^^^^

Are you implying that 1,000,000,000 (or 1e9) casts have been
generated by programmers since C89 was published? Or are you
counting multiple use of the same cast, when a program is
recompiled, copied, etc.? :-)

--
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cbfalconer at maineline dot net



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[Barry Schwarz]

Re: Redirecting input from file

On Wed, 04 Jul 2007 14:19:10 +0000, Richard Heathfield
<rjh@see.sig.in validwrote:

>dmoran21@cox.n et said:
>
><snip>
>

>I got my hands on the error messages that I got (I got into my e-mail
>at work, but since I'm not in the office today, I can't get to my
>code). I got the following:
>>
>Cannot convert 'void*' to 'float*' in function main(int, char * *)

>
>Either:
>
>(a) you forgot to #include <stdlib.h>

Then the message would say "cannot convert int to float*"


Remove del for email

[Richard Heathfield]

Re: Redirecting input from file

Barry Schwarz said:

On Wed, 04 Jul 2007 14:19:10 +0000, Richard Heathfield wrote:

>>dmoran21@cox. net said:
>>

>>Cannot convert 'void*' to 'float*' in function main(int, char * *)

>>
>>Either:
>>
>>(a) you forgot to #include <stdlib.h>

>
Then the message would say "cannot convert int to float*"

Oh, well done, sir. Yes, okay, so much for (a).

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

[Old Wolf]

Re: Redirecting input from file

On Jul 4, 7:12 am, "Army1987" <please....@for .itwrote:

Are you compiling it with a C++ compiler?
(If so, I'd be surprised of knowing free() works even without
casting the argument to void*).

In C++ there is an implicit conversion from
any object pointer type to void*, so there is
no need to cast any argument to free().

(Follow-ups set to c.l.c++)

[CBFalconer]

Re: Redirecting input from file

Old Wolf wrote:

On Jul 4, 7:12 am, "Army1987" <please....@for .itwrote:
>

>Are you compiling it with a C++ compiler? (If so, I'd be surprised
>of knowing free() works even without casting the argument to void*).

>
In C++ there is an implicit conversion from any object pointer type
to void*, so there is no need to cast any argument to free().
>
(Follow-ups set to c.l.c++)

Wrong. In C++ there is NO such implicit conversion. That is in C
only. Follow-ups set to c.l.c.

--
<http://www.cs.auckland .ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfoc us.com/columnists/423>
<http://www.aaxnet.com/editor/edit043.html>
cbfalconer at maineline dot net



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[Old Wolf]

Re: Redirecting input from file

On Jul 5, 11:26 am, CBFalconer <cbfalco...@yah oo.comwrote:

Old Wolf wrote:

On Jul 4, 7:12 am, "Army1987" <please....@for .itwrote:

>

Are you compiling it with a C++ compiler? (If so, I'd be
surprised of knowing free() works even without casting the
argument to void*).

>

In C++ there is an implicit conversion from any object pointer
type to void*, so there is no need to cast any argument to
free().

>
Wrong. In C++ there is NO such implicit conversion.

ISO/IEC 14882:1998, 4.10/2:
An rvalue of type "pointer to cv T," where T is an
object type, can be converted to an rvalue of type
"pointer to cv void." The result of converting a
"pointer to cv T" to a "pointer to cv void" points
to the start of the storage location where the object
of type T resides

You must be thinking of something else (perhaps
the fact that there's no implicit conversion
from void * to other pointer types).

That is in C only. Follow-ups set to c.l.c.

Not sure why you want to discuss C++ in c.l.c.

[Default User]

Re: Redirecting input from file

CBFalconer wrote:

Old Wolf wrote:

In C++ there is an implicit conversion from any object pointer type
to void*, so there is no need to cast any argument to free().

(Follow-ups set to c.l.c++)

>
Wrong. In C++ there is NO such implicit conversion. That is in C
only. Follow-ups set to c.l.c.

Yeah, there is. What's lacking is the implicit conversion from void* to
object pointer. Hence malloc() and friends require a cast in C++.




Brian

[Default User]

Re: Redirecting input from file

Old Wolf wrote:

In C++ there is an implicit conversion from
any object pointer type to void*, so there is
no need to cast any argument to free().
>
(Follow-ups set to c.l.c++)

Don't set follow-ups unless when the post wasn't cross there in the
first place.



Brian

[Richard Bos]

Re: Redirecting input from file

CBFalconer <cbfalconer@yah oo.comwrote:

Richard Heathfield wrote:

Drop all those silly casts. If that gives you diagnostic messages
at compile time or breaks the behaviour at runtime, *tell us*, and
we'll show you how to fix it. 99.9908237% of the time, casts
aren't the right fix. ^^^^^^^^^^

>
Are you implying that 1,000,000,000 (or 1e9) casts have been
generated by programmers since C89 was published? Or are you
counting multiple use of the same cast, when a program is
recompiled, copied, etc.? :-)

No; he's implying that of every 108976 casts written since C89 was
published, no more than 10 were The Right Thing. This would mean that
0.0091763324034 6...% of casts were right; but since there is only a
limited amount of certainty in the starting data, we should clip this
to, say, five significant digits, leaving 0.0091763% of right casts, and
therefore 99.9908237% wrong ones.

I must say, what with the enormous amount of badly written OS code out
there, much of it C-wannabe-C++, those figures sound reasonable to me.

Richard

[dmoran21@cox.net]

Re: Redirecting input from file

Here is my code as of now, as well as an input file and my output. I
am aware that I've got more error proofing to do, but this is what I
have right now.

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

int main(int argc, char *argv[])
{
/* Variable Declarations */
const int arraylength = 5000;
const int exiterrorcode = -1;
int count = 0;
int condition = 1;
float* precipvals = (float*)NULL;
float* precip3hrs = (float*)NULL;
long* date = (long*)NULL;
FILE *fpin;
FILE *fpout;

fpin = fopen(argv[1],"r");
fpout = fopen(argv[2],"w");

if(fpin == NULL || fpout == NULL) {
printf("Insuffi cient arguments\n");
exit(exiterrorc ode);
}

/* Array Allocation */
precipvals = (float*)malloc( sizeof(float) * arraylength);
precip3hrs = (float*)malloc( sizeof(float) * arraylength);
date = (long*)malloc(s izeof(long) * arraylength);

/* Calculation Section */
while(condition != EOF) {
condition = fscanf(fpin,"%l d,%f", &date[count],
&precipvals[count]);
if(count == 0) {
precip3hrs[count] = precipvals[count];
}
if(count == 1) {
precip3hrs[count] = precipvals[count] + precip3hrs[count-1];
}
if(count 1) {
precip3hrs[count] = precipvals[count] + precipvals[count-1] +
precipvals[count-2];
}
count++;
}

/* Output section */
for(count = 0; count < arraylength; count++) {
if(!(precipvals[count] == 0 && precip3hrs[count] == 0)) {
if(count == 0) {
printf("One hour precipitation: %2.2f Three hour precipitation
%2.2f\n",precip vals[count],precip3hrs[count]);
}
if(count == 1) {
printf("One hour precipitation: %2.2f Three hour precipitation
%2.2f\n",precip vals[count],precip3hrs[count]);
}
if(count 1) {
printf("One hour precipitation: %2.2f Three hour precipitation
%2.2f\n",precip vals[count],precip3hrs[count]);
}
}
}


/* Write to file */
for(count = 0; count < arraylength; count++) {
if(!(precipvals[count] == 0 && precip3hrs[count] == 0)) {
if(count == 0) {
fprintf(fpout," One hour precipitation: %2.2f Three hour
precipitation %2.2f\n",precip vals[count],precip3hrs[count]);
}
if(count == 1) {
fprintf(fpout, "One hour precipitation: %2.2f Three hour
precipitation %2.2f\n",precip vals[count],precip3hrs[count]);
}
if(count 1) {
fprintf(fpout, "One hour precipitation: %2.2f Three hour
precipitation %2.2f\n",precip vals[count],precip3hrs[count]);
}
}
}

fclose(fpin);
fclose(fpout);

/* Deallocation */
free(precipvals );
precipvals = (float*)NULL;
free(precip3hrs );
precip3hrs = (float*)NULL;
date = (long*)NULL;
free(date);

return 0;
}

Input file
200701010000,3. 58
200701010100,2. 33
200701010200,4. 55
200701010300,.2 9
200701010400,5. 18
200701010500,0
200701010600,0
200701010700,0
200701010800,0
200701010900,.3 4

Output file
One hour precipitation: 3.58 Three hour precipitation 3.58
One hour precipitation: 2.33 Three hour precipitation 5.91
One hour precipitation: 4.55 Three hour precipitation 10.46
One hour precipitation: 0.29 Three hour precipitation 7.17
One hour precipitation: 5.18 Three hour precipitation 10.02
One hour precipitation: 0.00 Three hour precipitation 5.47
One hour precipitation: 0.00 Three hour precipitation 5.18
One hour precipitation: 0.34 Three hour precipitation 0.34
One hour precipitation: 0.00 Three hour precipitation 0.34

TIA
Dave

[dmoran21@cox.net]

Re: Redirecting input from file

Now that I look at the code some more, I think there's a few areas
that I can remove i.e if(count = 0) etc. but I'm not sure.

Dave

[CBFalconer]

Re: Redirecting input from file

"dmoran21@cox.n et" wrote:

>
Here is my code as of now, as well as an input file and my output.
I am aware that I've got more error proofing to do, but this is
what I have right now.
>
#include <stdio.h>
#include <stdlib.h>
>
int main(int argc, char *argv[])
{
/* Variable Declarations */

To start with, control your indentation. 3 spaces is enough.
Don't use tabs for Usenet display.

const int arraylength = 5000;
const int exiterrorcode = -1;
int count = 0;
int condition = 1;
float* precipvals = (float*)NULL;
float* precip3hrs = (float*)NULL;
long* date = (long*)NULL;

The above casts are unnecessary, and only serve to hide possible
errors. This is not C++.

FILE *fpin;
FILE *fpout;
>
fpin = fopen(argv[1],"r");
fpout = fopen(argv[2],"w");
>
if(fpin == NULL || fpout == NULL) {
printf("Insuffi cient arguments\n");
exit(exiterrorc ode);
}

I believe passing NULL to fopen results in undefined behaviour.
Use argc.

>
/* Array Allocation */
precipvals = (float*)malloc( sizeof(float) * arraylength);
precip3hrs = (float*)malloc( sizeof(float) * arraylength);
date = (long*)malloc(s izeof(long) * arraylength);

Again, the casts are unnecessary etc.

>
/* Calculation Section */
while(condition != EOF) {
condition = fscanf(fpin,"%l d,%f", &date[count],
&precipvals[count]);

Here unless 'condition' is 2 fscanf failed. I also gave up
following the code.

--
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