1'This module contains this program's core procedures.
2Option Explicit
3
4Private Const EXPONENT_MASK As Long = &H7F800000   'Defines the exponent's bitmask.
5Private Const EXPONENT_SHIFT As Long = &H800000    'Defines the divisor used to right-shift the exponent's bits.
6Private Const MANTISSA_MASK As Long = &H7FFFFF     'Defines the mantissa's bitmask.
7Private Const SIGN_MASK As Long = &H80000000       'Defines the sign's bitmask.
8
9'The Microsoft Windows API constants used by this program.
10Private Declare Sub RtlMoveMemory Lib "kernel32" (ByRef Destination As Any, ByRef Source As Any, ByVal Length As Long)
11
12'This procedure is executed when this program is started.
13Public Sub Main()
14Dim Bytes As Long
15Dim Exponent As Long
16Dim Float As Single
17Dim Mantissa As Long
18Dim Reconstruction As Single
19Dim Sign As Long
20Dim TotalMantissa As Double
21
22   Debug.Print String$(50, "=")
23
24   Float = 0 '<---Replace with your own number.
25   Debug.Print "Float: "; Float
26   
27   RtlMoveMemory Bytes, Float, Length:=4
28   Debug.Print "Bytes: "; Hex$(Bytes); "h"
29
30   If (Bytes And SIGN_MASK) = SIGN_MASK Then Sign = -1 Else Sign = 1
31   Debug.Print "Sign: "; Sign
32
33   Exponent = ((Bytes And EXPONENT_MASK) \ EXPONENT_SHIFT)
34   Debug.Print "Exponent: "; Exponent; " (Real exponent: " & (Exponent - 127) & ")"
35
36   Mantissa = Bytes And MANTISSA_MASK
37   Debug.Print "Mantissa: "; Mantissa
38   
39   TotalMantissa = 1# + (Mantissa / 8388608#)
40   Debug.Print "Total Mantissa: "; TotalMantissa
41
42   Reconstruction = Sign * TotalMantissa * (2 ^ (Exponent - 127))
43
44   Debug.Print "Reconstructed: "; Reconstruction
45End Sub

1Attribute VB_Name = "Module1"
2Option Explicit
3
4Public Sub Main()
5Debug.Print QBasicFloatToString(1.233)
6
7End Sub
8
9Public Function QBasicFloatToString(Float As Single) As String
10Dim CommaPosition As Long
11Dim Digit As Long
12Dim Index As Long
13Dim Log10 As Long
14Dim Numbers As String
15Dim Result As String
16Dim Scaled As Double
17Dim SignStr As String
18
19    If Float = 0# Then
20        QBasicFloatToString = "0"
21        Exit Function
22    End If
23    
24    If Float < 0 Then
25        SignStr = "-"
26        Float = Abs(Float)
27    End If
28     
29    Log10 = CInt(Log(Float) / Log(10#))
30    
31    Scaled = Float / (10# ^ Log10)
32    
33    Numbers = vbNullString
34    For Index = 1 To 7
35        Digit = Int(Scaled)
36        Numbers = Numbers & CStr(Digit)
37        Scaled = (Scaled - Digit) * 10#
38    Next Index
39    
40    CommaPosition = Log10 + 1
41    
42    If CommaPosition > 0 And CommaPosition <= 7 Then
43        Result = Left$(Numbers, CommaPosition) & "." & Mid$(Numbers, CommaPosition + 1)
44    Else
45        If CommaPosition > 7 Then
46            Result = Numbers & String$(CommaPosition - 7, "0")
47        Else
48            Result = "0." & String$(Abs(CommaPosition), "0") & Numbers
49        End If
50    End If
51    
52    If InStr(Result, ".") > 0 Then
53        Do While Right$(Result, 1) = "0"
54            Result = Left$(Result, Len(Result) - 1)
55        Loop
56        If Right$(Result, 1) = "." Then Result = Left$(Result, Len(Result) - 1)
57    End If
58
59    QBasicFloatToString = SignStr & Result
60End Function