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Groups > comp.lang.c > #109508
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: obtaining a c value from a perl script |
| Date | 2017-05-08 09:14 -0700 |
| Organization | None to speak of |
| Message-ID | <lnlgq7ba11.fsf@kst-u.example.com> (permalink) |
| References | <emm0h5Foml1U1@mid.individual.net> <874lx6hqng.fsf@bsb.me.uk> <emojs3F9fp8U1@mid.individual.net> <oefke2$ktn$1@gioia.aioe.org> <enb0v4FrgpnU1@mid.individual.net> |
fred flintstone <fred@server.invalid> writes:
> On 05/04/2017 09:21 AM, Manfred wrote:
[snip]
> But is that the only fig leaf we need? Well no, as per your reply. I
> seem to be a bit rusty. Indeed, I found a post about how everything I
> used to know about how to print a double just went back to %f. Anyways,
> here was my attempt to write legal, contemporary C (cringe):
>
> #include <stdio.h>
>
> int main (int argc, char *argv[])
> {
> int count;
> double d;
>
> printf ("This program was called with \"%s\".\n",argv[0]);
argv[0] points to a string that represents the name of the program.
> if (argc = 2)
"=" is an assignment, so this test modifies the value of argc. An
assignment yields the value that was assigned, so the condition is
always true. If argc is 3, for example, this test will set it to 2 and
evaluate as a true condition. You want "if (argc == 2).
> {
> d = (double) argv[1];
argv[1] is a pointer of type char*. You cannot legally convert a
pointer to a floating-point type. (If it were legal, the resulting
double value would be meaningless.)
I presume you want, for example, the double value 1.5 given that argv[1]
points to the string "1.5". The simplest way to do this is
d = atof(argv[1]);
but that doesn't do any error checking. For error checking, use
strtod(). (Both are declared in <stdlib.h>.)
[...]
> If I'm tormenting this newsgroup by my very presence, just give me what
> I want, and no one gets hurt....
Changing your attitude would increase the odds of getting useful advice
here. You recently plonked someone who had just given you some very
good advice about how ask questions.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-04-30 04:36 -0700
Re: obtaining a c value from a perl script Noob <root@127.0.0.1> - 2017-04-30 14:48 +0200
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-01 02:25 -0700
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-01 08:46 -0700
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-03 02:12 -0700
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-03 11:48 +0100
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-30 16:16 +0100
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-01 04:18 -0700
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-01 13:41 +0100
Re: obtaining a c value from a perl script Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-03 05:10 -0700
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-03 15:00 +0100
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-03 08:55 -0700
Re: obtaining a c value from a perl script Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-03 09:02 -0700
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-03 17:22 +0100
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-08 01:43 -0700
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-08 09:06 -0700
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-09 00:35 -0700
Re: obtaining a c value from a perl script David Brown <david.brown@hesbynett.no> - 2017-05-09 13:59 +0200
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-08 02:45 -0700
Re: obtaining a c value from a perl script Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-08 04:39 -0700
solved Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-09 02:43 -0700
Re: solved Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-09 15:06 +0100
Re: solved Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-10 01:03 -0700
Re: solved Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-10 11:18 +0100
Re: solved Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-12 02:26 -0700
Re: solved Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-12 11:51 +0100
Re: solved Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-12 03:49 -0700
Re: solved Re: obtaining a c value from a perl script Manfred <invalid@invalid.add> - 2017-05-10 23:21 +0200
Re: solved Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-10 16:23 -0700
Re: solved Re: obtaining a c value from a perl script Robert Wessel <robertwessel2@yahoo.com> - 2017-05-11 15:57 -0500
Re: solved Re: obtaining a c value from a perl script Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-11 18:57 -0400
Re: solved Re: obtaining a c value from a perl script Robert Wessel <robertwessel2@yahoo.com> - 2017-05-11 18:38 -0500
Re: solved Re: obtaining a c value from a perl script Robert Wessel <robertwessel2@yahoo.com> - 2017-05-11 18:46 -0500
Re: solved Re: obtaining a c value from a perl script Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-11 21:11 -0400
Re: solved Re: obtaining a c value from a perl script Robert Wessel <robertwessel2@yahoo.com> - 2017-05-12 01:51 -0500
Re: solved Re: obtaining a c value from a perl script Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-14 23:49 -0400
Re: obtaining a c value from a perl script Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-09 07:46 -0700
Re: obtaining a c value from a perl script mark.bluemel@gmail.com - 2017-05-03 09:06 -0700
Re: obtaining a c value from a perl script gazelle@shell.xmission.com (Kenny McCormack) - 2017-05-03 17:02 +0000
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-08 01:51 -0700
Re: obtaining a c value from a perl script Manfred <noname@invalid.add> - 2017-05-04 18:21 +0200
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-08 03:52 -0700
Re: obtaining a c value from a perl script Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-08 08:38 -0400
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-08 09:14 -0700
Re: obtaining a c value from a perl script "James R. Kuyper" <jameskuyper@verizon.net> - 2017-05-08 12:17 -0400
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-08 09:26 -0700
Re: obtaining a c value from a perl script jameskuyper@verizon.net - 2017-05-08 11:02 -0700
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-08 11:39 -0700
Re: obtaining a c value from a perl script Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-09 07:16 -0700
Re: obtaining a c value from a perl script Keith Thompson <kst-u@mib.org> - 2017-05-09 08:18 -0700
Re: obtaining a c value from a perl script fred flintstone <fred@server.invalid> - 2017-05-10 00:29 -0700
Re: obtaining a c value from a perl script Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-10 05:26 -0700
Re: obtaining a c value from a perl script Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-08 18:20 +0100
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