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Re: Beginner--Need to test and check real input values

• To: mathgroup at smc.vnet.net
• Subject: [mg71595] Re: [mg71564] Beginner--Need to test and check real input values
• From: "厉正吉" <zhengji.li at gmail.com>
• Date: Fri, 24 Nov 2006 01:17:15 -0500 (EST)
• References: <200611231041.FAA25255@smc.vnet.net>

Lian,

This works:
c = 0;
While[! (Head[c] ===
   Real && 0 < c < 0.9), c = Input["Give a positive real value to c
 less than 0.9"]]
Print["c= ", c]

RealQ is not a built-in function of Mathematica. But we may define it as:

RealQ := Head[#] === Real &;

On 11/23/06, abdou.oumaima at hotmail.com <abdou.oumaima at hotmail.com> wrote:
> Hello Math Group,
>
> I'm using While to control a flow of input values. I need to give a positive and real value to a variable, let's call it "c" . I write the code bellow but when I excute it, I can put a string value and can return it. How can I control that please.
>
> c = 0;
> While[! (RealQ[c] && 0 < c < 0.9), c = Input["Give a positive real value to c
>   less than 0.9"]]
> Print["c= ", c]
>
> Greetings.
> Lian.
>

-- 
Li Zhengji
-------------------------------------------------------------
If all you have is a hammer, everything is a nail.
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• References:
  • Beginner--Need to test and check real input values
    • From: abdou.oumaima@hotmail.com