Re: complex variable

Re: complex variable

[Ankit Jain]

      1 #include<stdlib.h>
      2 #include<complex.h>
      3 #include<stdio.h>
      4
      5 int main()
      6 {
      7         FILE *fp;
      8         fp=fopen("test_data.dat","rb");
      9         int N=32,i=0;
     10         complex x,*in;
     11         in=malloc(sizeof(complex)*N);
     12         if (fread(in,16,32,fp) != 32)
     13          printf("error in reading from file
failed\n");
     14         else{
     15         for(i=0;i<N;i++)
     16           printf("%lf\t",*(in+i+0));
     17         }
     18         return 0;
     19 }

i am sorry but this code also gives the same error

error in reading from file failed

ankit
 --- Sriharsha Vedurmudi
<sriharsha.v@redpinesignals.com> wrote: 

---------------------------------
    Ankit Jain wrote:  
      1 #include<stdlib.h>      2 #include<complex.h> 
    3 #include<stdio.h>      4      5 int main()     
6 {      7         FILE *fp;      8        
fp=fopen("test_data.dat","rb");      9         int
N=32,i=0;     10         complex x,*in;     11        
in=malloc(sizeof(complex)*N);     12         if
(fread(in,16,32*16,fp) != 32)     13         
printf("error in reading from file failed\n");     14 
       else{     15         for(i=0;i<N;i++)     16   
       printf("%lf\t",*(in+i+0));     17         }    
18         return 0;     19 }it gives error"error in
reading the file"  

Which in the above errors (in Bold) is displayed.
Because, both of themare different. And I dont see any
means by which it would print theerror you specified.

Coming to fread, the third arguement should be 32 in
case you aretrying to read 32 items each of size 16
bytes and then the return valuewill be 32 in case it
actually reads 32 such items. In the abovestatement,
you have asked fread like this:

Read 32 * 16 elements (total of 512 elements) each 16
bytes long from'fp' and store tehm at 'in'. If you
dont read 32 such elements, printerror message. 

Can you see the ambiguity here (ask it to read 512
elements and compareif it reads 32).....

-Harsha
 

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Re: complex variable

[Patrick Percot]

On Mon, 6 Sep 2004 14:45:25 +0100 (BST), Ankit Jain <ankitjain1580@yahoo.com> wrote

>       1 #include<stdlib.h>
>       2 #include<complex.h>
>       3 #include<stdio.h>
>       4
>       5 int main()
>       6 {
>       7         FILE *fp;
>       8         fp=fopen("test_data.dat","rb");
>       9         int N=32,i=0;
>      10         complex x,*in;
>      11         in=malloc(sizeof(complex)*N);
>      12         if (fread(in,16,32,fp) != 32)
>      13          printf("error in reading from file
> failed\n");
>      14         else{
>      15         for(i=0;i<N;i++)
>      16           printf("%lf\t",*(in+i+0));
>      17         }
>      18         return 0;
>      19 }
> 
> i am sorry but this code also gives the same error
> 
> error in reading from file failed

So, the problem is with the data you are trying to read. 

Why don't you write :
  if (fread(in, sizeof(complex) , N, fp) != N)


[..Zappé 47 lignes et 1698 caractères..]

À+
PP
-- 
Groupe Morbihannais d'Utilisateurs de Logiciels Libres http://www.tuxbihan.org
GPG fingerprint = 1A4F E154 3D2C A20E E4CA  A543 7951 C5C2 E44A A0B5

Patrick Percot.

Re: complex variable

[Ankit Jain]

"fread and fwrite return the  number of items
successfully read "
well i am reading 32 complex neumbers...sorry i dont
understand why it whould be 16 and not 32?

ankit
 --- Patrick Percot <ppercot@free.fr> wrote: 
> On Mon, 6 Sep 2004 13:22:15 +0100 (BST), Ankit Jain
> <ankitjain1580@yahoo.com> wrote
> 
> >       1 #include<stdlib.h>
> >       2 #include<complex.h>
> >       3 #include<stdio.h>
> >       4
> >       5 int main()
> >       6 {
> >       7         FILE *fp;
> >       8         fp=fopen("test_data.dat","rb");
> >       9         int N=32,i=0;
> >      10         complex x,*in;
> >      11         in=malloc(sizeof(complex)*N);
> >      12         if (fread(in,16,32*16,fp) != 32)
> 
> The manual page says :
> 
> RETURN VALUE
>        fread and fwrite return the  number of items
> successfully read or
>        written  (i.e.,  not the  number  of 
> characters).   If an  error
>        occurs,  or the  end-of-file is  reached, the
>  return value  is a
>        short item count (or zero).
> 
> So if fread is OK, it returns 16 not 32.
> 
> >      13          printf("error in reading from
> file
> > failed\n");
> >      14         else{
> >      15         for(i=0;i<N;i++)
> >      16           printf("%lf\t",*(in+i+0));
> >      17         }
> >      18         return 0;
> >      19 }
> > 
> > it gives error
> > "error in reading the file"
> > 
> > whats wrong?
> > 
> > ankit
> > 
> >
>
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> 
> À+
> PP
> -- 
> Groupe Morbihannais d'Utilisateurs de Logiciels
> Libres http://www.tuxbihan.org
> GPG fingerprint = 1A4F E154 3D2C A20E E4CA  A543
> 7951 C5C2 E44A A0B5
> 
> Patrick Percot.
>  

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Re: complex variable

[Claudio Bley]

On Mon, Sep 06, 2004 at 01:47:58PM +0100, Ankit Jain wrote:
> "fread and fwrite return the  number of items
> successfully read "
> well i am reading 32 complex neumbers...

No, you're reading 32*16 == 512 elements (i.e. complex numbers) 
each 16 bytes in size.

Try:

  if(fread(in,sizeof(complex),32,fp) != 32)


HTH
Claudio

complex variable

[Ankit Jain]

      1 #include<stdlib.h>
      2 #include<complex.h>
      3 #include<stdio.h>
      4
      5 int main()
      6 {
      7         FILE *fp;
      8         fp=fopen("test_data.dat","rb");
      9         int N=32,i=0;
     10         complex x,*in;
     11         in=malloc(sizeof(complex)*N);
     12         if (fread(in,16,32*16,fp) != 32)
     13          printf("error in reading from file
failed\n");
     14         else{
     15         for(i=0;i<N;i++)
     16           printf("%lf\t",*(in+i+0));
     17         }
     18         return 0;
     19 }

it gives error
"error in reading the file"

whats wrong?

ankit

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Re: complex variable

[Ankit Jain]

well i had tried this also
fread(in,16,32*16,fp) != 32*16 earlier but dosent work
and gives the same error

actually i have 32 complex nos whose size is 16byte
each so total size is 32*16->its the size not the no.
of elements i am reading so i feel
fread(in,16,32*16,fp) != 32
this should be right?

ankit
 --- Ankit Jain <ankitjain1580@yahoo.com> wrote: 
>       1 #include<stdlib.h>
>       2 #include<complex.h>
>       3 #include<stdio.h>
>       4
>       5 int main()
>       6 {
>       7         FILE *fp;
>       8         fp=fopen("test_data.dat","rb");
>       9         int N=32,i=0;
>      10         complex x,*in;
>      11         in=malloc(sizeof(complex)*N);
>      12         if (fread(in,16,32*16,fp) != 32)
>      13          printf("error in reading from file
> failed\n");
>      14         else{
>      15         for(i=0;i<N;i++)
>      16           printf("%lf\t",*(in+i+0));
>      17         }
>      18         return 0;
>      19 }
> 
> it gives error
> "error in reading the file failed"
> 
> whats wrong?
> 
> ankit
> 
>
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