error when calculating root of negative number

[aleph01]

To get practice coding with AutoIt, I'm trying to code a root calculator. It calculates roots to the n^th power for positive numbers, but won't calculate an odd root of a negative number. For instance, when asked for the cube root of -27, it should return -3, but it returns an error instead. Everything else seems to work fine. Can anyone see an error in my code or is there a better way to approach this?

Thanks,

_aleph_

#include <math.au3>
dim $rootword
$odd = 0
$root = InputBox ("Root Calculator", "What root do you wish to calculate? (2 = square root, 3 = cube root, etc.")
If $root <= 0 Then
Msgbox (0, "Error", "Unable to perform zero or negative root calculations.")
Exit
EndIf
If $root = 2 Then
$rootword = ("square")
ElseIf $root = 3 Then
$rootword = ("cube")
Else
$rootword = $root & "th"
EndIf
$num = InputBox ("Root Calculator", "Of what number do you wish to calculate the root?")
If $num < 0 Then
$odd = _MathCheckDiv ($root, 2)
EndIf
If $odd <> 2 Then
MsgBox (0, "The " & $rootword & " root of " & $num & " is:", $num ^ (1/$root))
Else
MsgBox (0, "Unable to Calculate", "One cannot calculate an even root of a negative number, silly!")
EndIf

[JohnOne]

I don't think you can calculate the root of a negative number.

I've seen fellas come to blows about this in the pub.

I'm out of here.

[UEZ]

Complex numbers are not supported by AutoIt.

Have a look here how to get the root of negative numbers: http://en.wikipedia.org/wiki/Complex_number

Br,

UEZ

Edited April 26, 2012 by UEZ

[iamtheky]

or just calculate it all positive like, and return the negative.

#include <math.au3>
dim $rootword
$odd = 0
$root = InputBox ("Root Calculator", "What root do you wish to calculate? (2 = square root, 3 = cube root, etc.")
If $root <= 0 Then
Msgbox (0, "Error", "Unable to perform zero or negative root calculations.")
Exit
EndIf
If $root = 2 Then
$rootword = ("square")
ElseIf $root = 3 Then
$rootword = ("cube")
Else
$rootword = $root & "th"
EndIf
$num = InputBox ("Root Calculator", "Of what number do you wish to calculate the root?")
If $num < 0 Then
$odd = _MathCheckDiv ($root, 2)
EndIf
If $odd <> 2 and $num >= 0 Then
MsgBox (0, "The " & $rootword & " root of " & $num & " is:", $num ^ (1/$root))
Elseif $odd <> 2 and $num < 0 Then
$num = stringtrimleft ($num , 1)
$negcube = $num^(1/3)
$negcube = "-" & $negcube
MsgBox (0, '' , $negcube)
Else
MsgBox (0, "Unable to Calculate", "One cannot calculate an even root of a negative number, silly!")
EndIf

Edit - forgot about 0

Edited April 26, 2012 by boththose

[jdelaney]

aren't those imaginary

[jchd]

Imaginary? Geez, no!

The OP is asking the the cube root of -27.

[iamtheky]

This one makes Wolfram do it for you, at least until they change the slightest thing about their returns.

#include <inet.au3>
#include <array.au3>

$num = "-125"

$source = _inetgetsource ("http://www.wolframalpha.com/input/?i=" & $num & "^%281%2F3%29")

;~ msgbox (0, '' , $source)

$exp = stringregexp($source , 'scannerresult_0200_1(.*?)id="i_0200_1"' , 3)
$url = stringregexp($exp[0] , 'src="(.*?)"' , 3)

shellexecute($url[0])

[jdelaney]

well played, only math I kept up on (used in real world) was statistics

Edited April 26, 2012 by jdelaney