Mid() mismatch

[smountain]

Hello All,

The debugger points to the first use of mid() as 'Error 13' type mismatch.

The idea of the subroutine is to take a string like 2x^5-3x^2-5 and put the coefficients and exponents into arrays. Can anyone tell me where I am going wrong?

Private Sub loadfunc()

Dim xptr As Integer, i As Integer, ptr As Integer, signptr As Integer, posptr As Integer, negptr As Integer
Dim s As String, tempstr As String


ReDim c(n) As Double
ReDim e(n) As Double


s = TB_EQ


ptr = 1


For i = 1 To n
    If i = n Then
        c(i) = mid(s, ptr + 1)
    Else
        xptr = InStr(ptr, s, "x")
        posptr = InStr(ptr + 1, s, "+")
        negptr = InStr(ptr + 1, s, "-")
        If negptr = 0 Then
            signptr = posptr
        ElseIf posptr = 0 Then
            signptr = negptr
        ElseIf posptr < negptr Then
            signptr = posptr
        Else
            signptr = negptr
        End If
        tempstr = mid(s, ptr, xptr - ptr)
        c(i) = CDbl(tempstr)
        tempstr = mid(s, xptr + 2, signptr - (xptr + 2))
        e(i) = CDbl(tempstr)
        ptr = signptr
    End If
Next i




End Sub

[patel]

variable n is not defined in your code

[snb]

sub M_snb()
  sn=strconv("2x^5-3x^2-5",64)
end sub