integer <-> floating point conversion

[Kurt]

A device I communicate with sends to me two 16bit integers. But these 32 bits actually stand internal for a floating-point value. Is there in VB .NET an easy way to convert 4 bytes to a float and back the other way around?

[mutant]

Convert.ToDouble(someint)

This should help you.

 

[edit]fixed typo[/edit]

[Kurt]

No, this is not what I'm looking for. Probably my question is not very clear (and not very obvious). Following example describes what I need.

 

Suppose I get following two integers from the device I have to communicate with: 16455 and 44564

 

binary this is

16455 = 0100 0000 0100 0111

44564 = 1010 1110 0001 0100

 

putting them together

0100 0000 0100 0111 1010 1110 0001 0100

this should be a IEEE 754 - compliant represantation of the single precision value 3.12 !!!

 

So I look for a function that takes 16455 and 44564 as parameters and returns 3.12 .... and the other way arround, a function that takes 3.12 and returns an integer array with the values 16455 and 44564 in.

[divil]

You can achieve this by creating a structure and using an explicit field layout on it so the memory address used by the three variables you're interested in is shared:

 

Imports System
Imports System.Runtime.InteropServices

Namespace Test
   Public Class Test

       <StructLayout(LayoutKind.Explicit)> _
        Private Structure Shorts2Float
           <FieldOffset(0)> _
           Public s1 As UInt16
           <FieldOffset(2)> _
           Public s2 As UInt16
           <FieldOffset(0)> _
           Public f As Single
       End Structure

       Public Shared Sub Main()
           Dim s1 As UInt16 = Convert.ToUInt16(16455)
           Dim s2 As UInt16 = Convert.ToUInt16(44564)
           Dim s2f As Shorts2Float = New Shorts2Float
           s2f.s1 = s1
           s2f.s2 = s2
           Dim f As Single = s2f.f
           Debug.WriteLine("{0}", s2f.f.ToString())
       End Sub
   End Class

End Namespace

 

Something like that ought to get you started.

[Kurt]

Thanks a lot divil, this is a very nice and easy solution. I work some months with .NET now, but I never used attributes before. I didn't even know what those "<" and ">" signs where :-\

Have you got some links to articles about atributes, or some other things you can advise me to read?

[divil]

Attributes are great - but I don't know of any articles on them. MSDN probably has some good pages on the concept though.

[begin_with_A]

Do you know how to convert a number to a spelling string? For example

string method(int k) should return a string which will be k in spelling? E.g. k=10 then string should be "Ten" and not "10".

k=125 then it should say "hundred and twenty-five" etc.?

 

-A

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