Solved

convert two bytes into an integer

Posted on 2000-04-11
7
1,502 Views
Last Modified: 2012-06-22
Is this right?

eg
dim z1 as byte
dim z2 as byte
dim MyInt as integer

MyInt = -1 * (z1 * 256 + z2)

0
Comment
Question by:MitchBroadhead
7 Comments
 
LVL 3

Expert Comment

by:Gordonp
ID: 2703980
get rid of the -1 and your fine

MYInt = (z1 * 256) + z2

Gordon

0
 
LVL 3

Expert Comment

by:Lewy
ID: 2704005
You must test and handle the case where z1 is greater than 127 (The MyInt is negative). If not you gen an Overflow error

    If z1 And &H80 Then
        MyInt = ((z1 And &H7F) * 256 + z2) Or &H8000
    Else
        MyInt = z1 * 256 + z2
    End If
0
 
LVL 1

Author Comment

by:MitchBroadhead
ID: 2704056
Adjusted points from 5 to 10
0
ScreenConnect 6.0 Free Trial

Discover new time-saving features in one game-changing release, ScreenConnect 6.0, based on partner feedback. New features include a redesigned UI, app configurations and chat acknowledgement to improve customer engagement!

 
LVL 1

Author Comment

by:MitchBroadhead
ID: 2704057
What does 'z1 And &H80' mean?
0
 
LVL 2

Expert Comment

by:Crin
ID: 2704102
'z1 And &h80' maens logical binary operator. Select "And" word within VB environment and press F1 for more info.

Sincerely yours,

Crin
0
 
LVL 3

Accepted Solution

by:
Gordonp earned 10 total points
ID: 2704114
&H80 is a hex number = 128

(z1 And &H80) returns 128(&H80) is z1 is >= 128 and 0 if z1 < 128

Could rewrite it

IF z1 >= 128 then
   MyInt = ((z1 - 128) * 256 + z2) * -1
else
   MyInt = z1 * 256 + z2
End If

which is the same as lewys answers but using maths rather than bitwise manipulations.

Gordon
0
 

Expert Comment

by:itacan
ID: 2704138
Yes it is right
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction While answering a recent question about filtering a custom class collection, I realized that this could be accomplished with very little code by using the ScriptControl (SC) library.  This article will introduce you to the SC library a…
This article describes some techniques which will make your VBA or Visual Basic Classic code easier to understand and maintain, whether by you, your replacement, or another Experts-Exchange expert.
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question