Print DecToBin$(5)
Print DecToBin$(50)
Print DecToBin$(9000)

Print BinToDec$(DecToBin$(5)) '  101
Print BinToDec$(DecToBin$(50)) '110010
Print BinToDec$(DecToBin$(9000)) ' 10001100101000

End

Function DecToBin$ (digit As Integer)
    DecToBin$ = "Error"
    If digit < 1 Then
        Print " Error number invalid for conversion to binary"
        DecToBin$ = "error of input"
        Exit Function
    Else

        Dim As Integer TempD
        Dim binaryD As String
        binaryD = ""
        TempD = digit
        Do
            binaryD = Right$(Str$(TempD Mod 2), 1) + binaryD
            TempD = TempD \ 2
        Loop Until TempD = 0
        DecToBin$ = binaryD
    End If
End Function

Function BinToDec$ (digitB As String)
    BinToDec$ = "Error"
    If Len(digitB) < 1 Then
        Print " Error number invalid for conversion to decimal"
        BinToDec$ = "error of input"
        Exit Function
    Else
        Dim As Integer TempD
        Dim binaryD As String
        binaryD = digitB
        TempD = 0
        Do
            TempD = TempD + ((2 ^ (Len(binaryD) - 1)) * Val(Left$(binaryD, 1)))
            binaryD = Right$(binaryD, Len(binaryD) - 1)
        Loop Until Len(binaryD) = 0
        BinToDec$ = LTrim$(Str$(TempD))
    End If
End Function