by Aidan (3 Submissions)
Category: VB function enhancement
Compatability: Visual Basic 3.0
Difficulty: Unknown Difficulty
Date Added: Wed 3rd February 2021
Rating: 
(3 Votes)
Converts a number of any base into any other base. For example, it
can convert a binary number into decimal, octal, hexadecimal, etc. and
back again. This is an improvement over the previous version as it can now
handle the 'double' data-type. (Very Large Numbers). It is useful for
converting DWords from the registry, etc.
Inputs
1. A Number to Convert
2. The base of that Number
3. The base of the desired number
Code Returns
A string containing the number in the specified base
API Declarations
VBcoders' Place the following code in a form...
Private Sub Form_Load()
Debug.Print ConvertBase("10", 10, 16)
End Sub
Public Function ConvertBase(NumIn As String, BaseIn As Integer,_
BaseOut As Integer) As String
' Converts a number from one base to another
' E.g. Binary = Base 2
' Octal = Base 8
' Decimal = Base 10
' Hexadecimal = Base 16
' NumIn is the number which you wish to convert
' (A string including characters 0 - 9, A - Z)
' BaseIn is the base of NumIn (An integer value in
' decimal between 1 & 36)
' BaseOut is the base of the number the function
' returns (An integer value in decimal between 1 & 36)
' Returns a string in the desired base containing the
' characters 0 - 9, A - Z)
' e.g. Debug.Print ConvertBase ("42", 8, 16) converts the octal number 42 into hexadecimal
' Returns the string "22"
' Returns the word "Error" if any of the input values
' are incorrect
Dim i As Integer, CurrentCharacter As String,_
CharacterValue As Integer, PlaceValue As Integer,_
RunningTotal As Double, Remainder As Double,_
BaseOutDouble As Double, NumInCaps As String
' Ensure input data is valid
If NumIn = "" Or BaseIn < 2 Or BaseIn > 36 Or_
BaseOut < 1 Or BaseOut > 36 Then
ConvertBase = "Error"
Exit Function
End If
' Ensure any letters in the input mumber are capitals
NumInCaps = UCase$(NumIn)
' Convert NumInCaps into Decimal
PlaceValue = Len(NumInCaps)
For i = 1 To Len(NumInCaps)
PlaceValue = PlaceValue - 1
CurrentCharacter = Mid$(NumInCaps, i, 1)
CharacterValue = 0
If Asc(CurrentCharacter) > 64 And _
Asc(CurrentCharacter) < 91 Then _
CharacterValue = Asc(CurrentCharacter) - 55
If CharacterValue = 0 Then
' Ensure NumIn is correct
If Asc(CurrentCharacter) < 48 Or _
Asc(CurrentCharacter) > 57 Then
ConvertBase = "Error"
Exit Function
Else
CharacterValue = Val(CurrentCharacter)
End If
End If
If CharacterValue < 0 Or CharacterValue > BaseIn - 1 Then
' Ensure NumIn is correct
ConvertBase = "Error"
Exit Function
End If
RunningTotal = RunningTotal + CharacterValue *_
(BaseIn ^ PlaceValue)
Next i
' Convert Decimal Number into the desired base using
' Repeated Division
Do
BaseOutDouble = CDbl(BaseOut)
Remainder = ModDouble(RunningTotal, BaseOutDouble)
RunningTotal = (RunningTotal - Remainder) / BaseOut
If Remainder >= 10 Then
CurrentCharacter = Chr$(Remainder + 55)
Else
CurrentCharacter = Right$(Str$(Remainder),_
Len(Str$(Remainder)) - 1)
End If
ConvertBase = CurrentCharacter & ConvertBase
Loop While RunningTotal > 0
End Function
Public Function ModDouble(NumIn As Double, DivNum As Double) As Double
' Returns the Remainder when a number is divided by another
' (Works for double data-type)
ModDouble = NumIn - (Int(NumIn / DivNum) * DivNum)
End Function
