paul@tucson.sie.arizona.edu (Paul Sanchez) (11/25/90)
I am using the Zortech C/C++ compiler, v.2.1 on an IBM PS-2/80 running
DOS 3.3. Overall I've been very happy with it, but recently I've run
into a couple of snags. Any help would be appreciated:
1) I appear to be running into the 64k barrier. Is there any way I
can create a vector of doubles >8k in length? (I am writing software
for time series analysis, and I'd like to be able to go up to about
50k for the length of my vector.) I compiled using the large model,
thinking that I would get far pointers automatically, but it didn't
seem to work.
2) The "%g" format in printf works as described by K&R II, but is
different from all of the UNIX implementations I deal with and from
Microsoft. The ZTC version loses significant digits. This is
illustrated by the small program below:
#include <stdio.h>
main()
{
double x;
for (x = 1.23456789e-5; x < 1e5; x *= 10.0)
printf("%8.3g\n", x);
}
with ZTC produces:
1.235e-005
0
0.001
0.012
0.123
1.235
12.346
123.457
1234.568
1.235e+004
while with GNU cc, Microsoft, Berkeley cc, and others it produces:
1.23e-05
0.000123
0.00123
0.0123
0.123
1.23
12.3
123
1.23e+03
1.23e+04
the latter is a heck of a lot better for labelling graphs, which is what
I'm trying to do. What does the ANSI standard have to say about this?
--paul sanchez
paul@tucson.sie.arizona.edubright@nazgul.UUCP (Walter Bright) (11/27/90)
In article <PAUL.90Nov24170411@tucson.sie.arizona.edu> paul@tucson.sie.arizona.edu (Paul Sanchez) writes:
/I am using the Zortech C/C++ compiler, v.2.1 on an IBM PS-2/80 running
/DOS 3.3.
/1) I appear to be running into the 64k barrier. Is there any way I
/can create a vector of doubles >8k in length?
Sure. Declare:
double *a[10];
for (i = 0; i < 10; i++)
a[i] = (double *) malloc(4096 * sizeof(double));
To access it:
#define a(j) a[j>>12][j&(4096-1)]
a(m) = y;
x = a(n);
/2) The "%g" format in printf works as described by K&R II, but is
/different from all of the UNIX implementations I deal with and from
/Microsoft.
This will be fixed.