Function cuberoot(x As Double) As Double Dim s, prev Dim positive As Long
If x = 0 Then Exit Function if x > 0 Then positive = 1 Else positive = 0:x = -x If x > 1 Then s = x Else s = 1
Do prev = s: s = (x / (s * s) + 2 * s) / 3 Loop while (s < prev) If (positive) Then cuberoot = prev Else cuberoot = -prev End Function
Function cuberoot2(x As Double) As Double Dim s, t, prev Dim positive As Long
If x = 0 Then Exit Function if x > 0 Then positive = 1 Else positive = 0:x = -x If x > 1 Then s = x Else s = 1
Do prev = s: t = s * s: s = s + (x - t * s) / (2 * t + x / s) Loop while (s < prev) If (positive) Then cuberoot2 = prev Else cuberoot2 = -prev End Function
' Function lcuberoot(x As Double) As Double Dim s
If x = 0 Then Exit Function s = cuberoot(x) lcuberoot = (x / (s * s) + 2 * s) / 3 End Function
#N88BASIC Dim i As Long
For i=0 To 20 Print i, cuberoot(i), cuberoot2(i), lcuberoot(i) Next
