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Re: I am learning C: a little problem with a simple source code

From Ian Collins <ian-news@hotmail.com>
Newsgroups comp.lang.c
Subject Re: I am learning C: a little problem with a simple source code
Date 2011-11-02 08:06 +1300
Message-ID <9hau9pFelvU2@mid.individual.net> (permalink)
References <f98781ff-2685-42af-bc3f-73ab27f898dc@d37g2000prg.googlegroups.com> <27db9617-8ff5-455a-8a90-ed40c1e4b7c2@p20g2000prm.googlegroups.com> <slrn3vfsjb097k.765.ike@sverige.freeshell.org> <3cd13578-0463-46aa-9dae-9a548afb5117@l19g2000yqc.googlegroups.com>

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On 11/ 2/11 07:51 AM, zemir wrote:
> Hi all and thanks for your suggestions, but i have solved. I think my
> solution it is not good solution and more of you will be not very
> happy but it seems to work fine, very fine. Please read:
>
> #include<stdio.h>;
> #include<math.h>;
> const float Pi = 3.14159265358979323846;

Why don't you use doubles?

> float area(float r)
> {                                                  /*define area
> function*/
> 	return(r*r*Pi);
> }
> float perimeter(float r) {                                         /
> *define perimeter function*/
> 		return(2*Pi*r);
> }
> void main() {

This should be int main().  On modern compilers, this won't compile 
because you are returning values.

> 	system("cls");

This won't do anything on a system without a "cls" command.

> 	float r=0; int c;/*define radius and c variable used to control the
> behaviour of program*/
> 	printf("This programm calculate Area and Perimenter of a Circle");
> 	printf("\n\nPlease insert radius value (in cm): "); /*input of the
> radius value*/
> 	scanf("%f",&r);
> if(r>0) {

It would be better to test the return of scanf rather than r.

> 	printf("Area is cm2: ");
> 	printf("%.2f", area(r));                                /*call area
> function*/
> 	printf("\nPerimeter is cm: ");
> 	printf("%.2f", perimeter(r));                       	/*call perimeter
> function*/
> 	} else {
> 		printf("Value must to be a valid number\n");
> 		printf("Press anykey to continue");
> 		c=getch();

getch() is non-standard.

> 		system("circle");

Are you trying to get the program to invoke its self?  Not a good idea!

> 		return 0;
> 	}
> 	printf("\nDo you want to continue? (y or elsewhere to exit)");
> 	c=getch();
> 	if(c==121) {

Why 121?  Why don't you use a character ('y')?

> 		system("circle");
> 		return 0;
> 	}
> }
>
> Then i have another question about variable c: the y value of int c, i
> think, it is ascii code so it is the same in all the system?

As long as the system uses ASCII!  Never use character values, use the 
character.

-- 
Ian Collins

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I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 08:27 -0700
  Re: I am learning C: a little problem with a simple source code Mark Bluemel <mark_bluemel@pobox.com> - 2011-11-01 15:49 +0000
  Re: I am learning C: a little problem with a simple source code nroberts <roberts.noah@gmail.com> - 2011-11-01 08:52 -0700
  Re: I am learning C: a little problem with a simple source code jt@toerring.de (Jens Thoms Toerring) - 2011-11-01 16:22 +0000
  Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-01 09:31 -0700
    Re: I am learning C: a little problem with a simple source code Ike Naar <ike@sverige.freeshell.org> - 2011-11-01 16:57 +0000
      Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 11:51 -0700
        Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-01 15:04 -0400
          Re: I am learning C: a little problem with a simple source code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-01 20:21 +0000
            Re: I am learning C: a little problem with a simple source code jacob navia <jacob@spamsink.net> - 2011-11-01 21:41 +0100
        Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-02 08:06 +1300
          Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:17 -0700
            Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-01 16:24 -0400
              Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:27 -0700
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2011-11-01 20:24 -0700
                Re: I am learning C: a little problem with a simple source code gazelle@shell.xmission.com (Kenny McCormack) - 2011-11-02 10:24 +0000
                Re: I am learning C: a little problem with a simple source code "BartC" <bc@freeuk.com> - 2011-11-02 11:04 +0000
                Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-02 07:41 -0400
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-02 18:00 +0000
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2011-11-02 14:06 -0700
                Re: I am learning C: a little problem with a simple source code John Bode <jfbode1029@gmail.com> - 2011-11-03 15:05 -0700
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 22:55 -0800
                Re: I am learning C: a little problem with a simple source code jgk@panix.com (Joe keane) - 2012-01-26 15:59 +0000
                Re: I am learning C: a little problem with a simple source code Fritz Wuehler <fritz@spamexpire-201201.rodent.frell.theremailer.net> - 2012-01-27 20:28 +0100
                Re: I am learning C: a little problem with a simple source code Markus Wichmann <nullplan@gmx.net> - 2012-01-28 14:11 +0100
                Re: I am learning C: a little problem with a simple source code Shao Miller <sha0.miller@gmail.com> - 2012-01-29 09:34 -0500
                Re: I am learning C: a little problem with a simple source code Markus Wichmann <nullplan@gmx.net> - 2012-01-30 13:38 +0100
                Re: I am learning C: a little problem with a simple source code Shao Miller <sha0.miller@gmail.com> - 2012-01-30 12:10 -0500
                Re: I am learning C: a little problem with a simple source code Zoltan Kocsi <zoltan@bendor.com.au> - 2012-01-29 08:55 +1100
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-31 21:48 -0800
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-31 21:46 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-01-31 22:30 -0800
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-08 10:11 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-08 13:51 -0800
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-09 12:51 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-09 13:36 -0800
                Re: I am learning C: a little problem with a simple source code jacob navia <jacob@spamsink.net> - 2012-03-09 23:50 +0100
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-09 15:01 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-09 16:21 -0800
                Re: I am learning C: a little problem with a simple source code gazelle@shell.xmission.com (Kenny McCormack) - 2012-03-10 00:57 +0000
                Re: I am learning C: a little problem with a simple source code jacob navia <jacob@spamsink.net> - 2012-03-10 13:37 +0100
                Re: I am learning C: a little problem with a simple source code gazelle@shell.xmission.com (Kenny McCormack) - 2012-03-10 13:58 +0000
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-10 12:24 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-10 14:16 -0800
                Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-11 12:50 -0700
                Re: I am learning C: a little problem with a simple source code Philip Lantz <prl@canterey.us> - 2012-03-11 00:57 -0800
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-11 03:20 -0700
                Re: I am learning C: a little problem with a simple source code Philip Lantz <prl@canterey.us> - 2012-03-12 02:10 -0700
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2012-03-12 10:49 -0700
                Re: I am learning C: a little problem with a simple source code Philip Lantz <prl@canterey.us> - 2012-03-14 01:16 -0700
                Re: I am learning C: a little problem with a simple source code Robert Miles <milesrf@Usenet-News.net> - 2012-04-15 06:53 -0500
                Re: I am learning C: a little problem with a simple source code Nomen Nescio <nobody@dizum.com> - 2012-04-15 19:45 +0200
                Re: I am learning C: a little problem with a simple source code Philip Lantz <prl@canterey.us> - 2012-04-15 15:06 -0700
                Re: I am learning C: a little problem with a simple source code 88888 Dihedral <dihedral88888@googlemail.com> - 2012-04-16 10:56 -0700
                Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-03 10:19 +1300
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-02 21:10 +0000
                Re: I am learning C: a little problem with a simple source code Kaz Kylheku <kaz@kylheku.com> - 2011-11-03 05:13 +0000
              Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:29 -0700
            Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-01 21:44 +0000
              Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-03 06:33 -0700
                Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-03 07:05 -0700
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-03 15:32 -0700
                Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-04 01:44 -0700
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-04 07:30 -0700
                Re: I am learning C: a little problem with a simple source code John Gordon <gordon@panix.com> - 2011-11-04 16:03 +0000
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-04 09:20 -0700
                Re: I am learning C: a little problem with a simple source code John Gordon <gordon@panix.com> - 2011-11-04 16:45 +0000
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-04 11:59 -0700
                Re: I am learning C: a little problem with a simple source code John Gordon <gordon@panix.com> - 2011-11-04 19:32 +0000
                Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-05 04:07 -0700
                Re: I am learning C: a little problem with a simple source code John Gordon <gordon@panix.com> - 2011-11-04 16:54 +0000
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-04 11:58 -0700
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 18:25 +0100
                Re: I am learning C: a little problem with a simple source code gordonb.e1fpi@burditt.org (Gordon Burditt) - 2011-11-04 13:50 -0500
                Re: I am learning C: a little problem with a simple source code Pasquale Frega <zemir_fp@libero.it> - 2011-11-04 11:57 -0700
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2011-11-04 14:44 -0700
                Re: I am learning C: a little problem with a simple source code "osmium" <r124c4u102@comcast.net> - 2011-11-04 14:03 -0500
                Re: I am learning C: a little problem with a simple source code Kaz Kylheku <kaz@kylheku.com> - 2011-11-04 21:37 +0000
                Re: I am learning C: a little problem with a simple source code Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-06 12:20 +0200
                Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-04 08:32 -0700
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-04 09:04 -0700
                Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-04 10:28 -0700
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-03 18:35 +0000
                Re: I am learning C: a little problem with a simple source code Pasquale Frega <zemir_fp@libero.it> - 2011-11-03 14:50 -0700
                Re: I am learning C: a little problem with a simple source code Keith Thompson <kst-u@mib.org> - 2011-11-03 15:59 -0700
                Re: I am learning C: a little problem with a simple source code Pasquale Frega <zemir_fp@libero.it> - 2011-11-04 12:00 -0700
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 20:58 +0100
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 21:13 +0100
                Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-04 01:56 -0700
                Re: I am learning C: a little problem with a simple source code Pasquale Frega <zemir_fp@libero.it> - 2011-11-04 12:12 -0700
                Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-05 10:09 +1300
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-03 15:32 -0700
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-03 22:53 +0000
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-03 17:57 -0700
                Re: I am learning C: a little problem with a simple source code Robert Wessel <robertwessel2@yahoo.com> - 2011-11-03 21:35 -0500
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-04 03:31 +0000
                Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-04 02:25 -0700
                Re: I am learning C: a little problem with a simple source code Kulin Remailer <remailer@reece.net.au> - 2011-11-03 22:47 +0000
                Re: I am learning C: a little problem with a simple source code Bill Reid <hormelfree@gmail.com> - 2011-11-03 16:14 -0700
                Re: I am learning C: a little problem with a simple source code Robert Wessel <robertwessel2@yahoo.com> - 2011-11-03 21:55 -0500
                Re: I am learning C: a little problem with a simple source code Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-04 08:10 -0700
                Re: I am learning C: a little problem with a simple source code ImpalerCore <jadill33@gmail.com> - 2011-11-04 14:21 -0700
                Re: I am learning C: a little problem with a simple source code Robert Wessel <robertwessel2@yahoo.com> - 2011-11-04 16:31 -0500
                Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-05 10:41 +1300
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-04 21:38 +0000
                Re: I am learning C: a little problem with a simple source code Robert Wessel <robertwessel2@yahoo.com> - 2011-11-04 22:18 -0500
                Re: I am learning C: a little problem with a simple source code Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-05 11:11 -0400
                Re: I am learning C: a little problem with a simple source code Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-05 11:13 -0400
                Re: I am learning C: a little problem with a simple source code Robert Wessel <robertwessel2@yahoo.com> - 2011-11-05 23:35 -0500
                Re: I am learning C: a little problem with a simple source code Seebs <usenet-nospam@seebs.net> - 2011-11-06 07:40 +0000
                Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-04 18:15 -0400
                Re: I am learning C: a little problem with a simple source code ImpalerCore <jadill33@gmail.com> - 2011-11-04 20:00 -0700
                Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-04 23:19 -0400
                Re: I am learning C: a little problem with a simple source code ImpalerCore <jadill33@gmail.com> - 2011-11-04 20:33 -0700
                Re: I am learning C: a little problem with a simple source code Kaz Kylheku <kaz@kylheku.com> - 2011-11-05 03:52 +0000
                Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-05 17:01 +1300
                Re: I am learning C: a little problem with a simple source code ImpalerCore <jadill33@gmail.com> - 2011-11-04 21:48 -0700
          Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:19 -0700
            Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-02 09:26 +1300
          Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:23 -0700
            Re: I am learning C: a little problem with a simple source code Ian Collins <ian-news@hotmail.com> - 2011-11-02 09:27 +1300
              Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 13:31 -0700
        Re: I am learning C: a little problem with a simple source code jt@toerring.de (Jens Thoms Toerring) - 2011-11-01 22:48 +0000
          Re: I am learning C: a little problem with a simple source code Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 23:09 -0800
        Re: I am learning C: a little problem with a simple source code gordonb.prbii@burditt.org (Gordon Burditt) - 2011-11-01 21:24 -0500
        Re: I am learning C: a little problem with a simple source code Dann Corbit <dcorbit@connx.com> - 2011-11-02 21:03 -0700
          Re: I am learning C: a little problem with a simple source code Ike Naar <ike@sverige.freeshell.org> - 2011-11-03 06:39 +0000
          Re: I am learning C: a little problem with a simple source code Barry Schwarz <schwarzb@dqel.com> - 2011-11-03 18:33 -0700
            Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-04 03:03 -0700
              Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 11:40 +0100
              Re: I am learning C: a little problem with a simple source code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-04 11:36 +0000
                Re: I am learning C: a little problem with a simple source code Kaz Kylheku <kaz@kylheku.com> - 2011-11-04 15:58 +0000
          Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 07:24 +0100
            Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 10:28 +0100
              Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 16:02 +0100
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 16:20 +0100
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-04 16:39 +0100
            Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-06 18:07 +0100
              Re: I am learning C: a little problem with a simple source code Barry Schwarz <schwarzb@dqel.com> - 2011-11-06 09:59 -0800
                Re: I am learning C: a little problem with a simple source code "io_x" <a@b.c.invalid> - 2011-11-06 19:23 +0100
                Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-06 15:23 -0500
      Re: I am learning C: a little problem with a simple source code zemir <zemir_fp@libero.it> - 2011-11-01 11:52 -0700
        Re: I am learning C: a little problem with a simple source code "BartC" <bc@freeuk.com> - 2011-11-01 23:02 +0000
  Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-02 03:53 -0700
    Re: I am learning C: a little problem with a simple source code James Kuyper <jameskuyper@verizon.net> - 2011-11-02 08:03 -0400
      Re: I am learning C: a little problem with a simple source code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-02 06:11 -0700

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