printf("%e", 0.0) prints with exponent e+01

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2 total messages Started by Craig Chamberlain Tue, 22 Dec 1992 15:20

Author: Craig Chamberlain
Date: Tue, 22 Dec 1992 15:20

31 lines
1156 bytes

Why does the floating value 0.0 print with an exponent
of +01 in printf %e format?  It is printed as 0.000000e+00
on the DECstation and VAX.

/* printf_zero.c */

#include <stdio.h>


int
main (argc, argv)
int argc;
char *argv [];

{
  double dr1;


  dr1 = 0.0;
  printf("dr1 is %e  %f  %g\n", dr1, dr1, dr1);

} /* main */

$ cc/standard=vaxc/float=ieee_float printf_zero.c
$ link printf_zero
$ r printf_zero
dr1 is 0.000000e+01  0.000000  0
-- 
(My opinions do not necessarily represent those of my employer.)
Craig Chamberlain, Software Engineer, Applicon Schlumberger
Ann Arbor, Michigan  chamber@ann-arbor.applicon.slb.com  (313) 995-6310

Re: printf("%e", 0.0) prints with exponent e+01

Author: Carl Fogelin
Date: Tue, 22 Dec 1992 17:54

39 lines
1462 bytes

In article 21980@ann-arbor.applicon.slb.com, chamber@mailhost.aa.cad.slb.com (Craig Chamberlain) writes:
>Why does the floating value 0.0 print with an exponent
>of +01 in printf %e format?  It is printed as 0.000000e+00
>on the DECstation and VAX.
>
>/* printf_zero.c */
>
>#include <stdio.h>
>
>
>int
>main (argc, argv)
>int argc;
>char *argv [];
>
>{
>  double dr1;
>
>
>  dr1 = 0.0;
>  printf("dr1 is %e  %f  %g\n", dr1, dr1, dr1);
>
>} /* main */
>
>$ cc/standard=vaxc/float=ieee_float printf_zero.c
>$ link printf_zero
>$ r printf_zero
>dr1 is 0.000000e+01  0.000000  0
>-- 

Now that's bizarre.  I looked up the fprintf's "e" format in the ANSI standard
and it states:

     4.9.6.1   "...  If the value is zero, the exponent is zero."

I think you need an answer from DEC.

Carl C. Fogelin                  "This is strictly my own opinion."
(fogelinc@cyanamid.com)

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