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GTBecker
Joined: 18 Jan 2006
Posts: 457
Location: Cape Coral
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Posted: 17 February 2010, 19:23 PM Post subject: Fixed-point Fmt |
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Fmt()'s handling of small and large values, replacing a fixed number of fractional digits with exponential notation, is problematic.
To avoid that behavior, I've often converted the value to a fixed-length string integer and inserted the decimal point with Mid(). An attempt to generalize that to a flexible function is: | Code: | function FmtX(byval ValIn as single, byval Digits as byte) as string
dim str as string
str = cstr(clng(abs(ValIn) * 10.0^Digits + 10.0^(Digits+1)))
str = mid(str,2,1) &"."& mid(str,3,Digits)
if (ValIn < 0.0) and (abs(ValIn) >= 0.5*10.0^-cint(Digits)) then ' prevent -0.0
str = "-" & str
end if
FmtX = trim(str)
end function |
This works fine for absolute values less than 10.0 but isn't generalized sufficiently to work with larger values which, I think, will need a series of integer decade decisions or a log10 to properly place the decimal point. Is there a better way to deal with this? |
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kurakaira
Joined: 21 Mar 2007
Posts: 32
Location: Finland
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Posted: 11 December 2010, 15:03 PM Post subject: FMT() |
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I haven't had a problem with FMT(LargeNumbers) but with values near zero ... they are a problem .
Since my programs usually follow this formula , Read ADC / other sensors -> Write to display ( using FMT ) , Loop .
My workaround so far has been this ,
if BoostS > (-0.01) and BoostS < 0.01 then
BoostS = 0.0
else
Call WriteLCD
End if
Would it be possible to add a FMTEX() that would not display the scientific notation ?
A new project with a ZX-40r processor ,
www.dlsrevolution.com
The ZX handles gear changing , battery voltages & fuses , amplifier heating & temperatures and door opening ... amongst other little things .
Everything is controlled by a 4.3" touchscreen from Reach Tech . |
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dkinzer
Site Admin
Joined: 03 Sep 2005
Posts: 2499
Location: Portland, OR
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Posted: 11 December 2010, 16:09 PM Post subject: Re: FMT() |
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| kurakaira wrote: | | Would it be possible to add a FMTEX() that would not display the scientific notation ? |
Some time ago, I posted a collection of formatting routines that all generate output to a character array. The FmtFloat() routine will probably do what you need and, if not, could probably be modified slightly to fit your needs. Here is some example code showing how it works with large and small floating point values, using FmtFloat() to implement FmtEx(). | Code: | Sub Main()
Debug.Print FmtEx(1000000.00001, 5)
Debug.Print FmtEx(1.00001, 5)
Debug.Print FmtEx(0.00001, 5)
End Sub
Function FmtEx(ByVal f as Single, ByVal decPlaces as Byte) as String
Dim buf(1 to 20) as Byte
Dim width as Byte
Call FmtFloat(f, decPlaces, buf, width)
FmtEx = MakeString(buf.DataAddress, width)
End Function |
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