Problem with power...

BlitzMax Forums/BlitzMax Programming/Problem with power...

McFox

(Posted 2006) [#1]

Hello,
Can someone explain me that :

SuperStrict
Function Power:Long(a:Long , b:Long)
	Return a ^ b
EndFunction

Print String(Long(Long(4)^Long(3)))
Print String(Power(4,3))

why my Power function returns me 63 ?

TIA

McFox

assari

(Posted 2006) [#2]

4^3 is a float operation that did not quite make 64.
try it out with return(a^b)*10000. the 63.9999 float was casted to 63 which is not mathematically correct but apparently is the standard way of doing things.

Don't know why the other way produces a 64 but there is only a small difference b/w 64.000001 and 63.9999 :)

N	(Posted 2006) [#3]

Could do something like this:

Function Power:Long( a:Long, b:Long )
    Local Round:Double( in:Double )
    
    out:Double = a^b
    If Abs(out Mod 1) >= .5 Then
        round = Ceil
    Else
        round = Floor
    EndIf
    
    Return Round(out)
End Function

TomToad

(Posted 2006) [#4]

Or you can just do
return Long(out+.5)