?
Solved

Convert integer into a bitarray?

Posted on 2004-10-04
6
Medium Priority
?
710 Views
Last Modified: 2008-03-10
how can i turn say integer 129 into something like 10000001 that i can then loop through and tell whether it's a 1 or 0 at any point or on/off/whatever.  I can write all my own custom stuff if need be, but i didn't know if vb had something like this already?


like

dim test as integer = 129

dim test2 as arrayofsomesort

test2 = turntobits(test)

for a = 0 to test2.count - 1

if test2(a) = 1 then
'fire something here
end if

next

get where i'm doing?  real similiar to the concept of flags in Quake2 configs where to set certain options you add numbers and together and put taht number in your config.

Thanks,
Nick



0
Comment
Question by:NickUA
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 8

Accepted Solution

by:
gregasm earned 672 total points
ID: 12223194
Use static methods of the BitConverter class.

byte[] myBytes = BitConverter.GetBytes(myint);

Then you can use the byte array and go deeper into bits.
0
 
LVL 6

Assisted Solution

by:mogun
mogun earned 664 total points
ID: 12224159
Hi,

You don't have to loop through the bit array to check whether a bit is set or not.. Instead you can use bit operators to evaluate whether a bit is set or not....The following is code that uses && operator and << (left shift ) operators to evaluate whether a bit is set or not..

    Public Function IsBitSet(ByVal iConfig As Integer, ByVal iBitToCheck As Integer) As Boolean
        If (iConfig And (1 << (iBitToCheck - 1))) >= 1 Then
            Return True
        Else
            Return False
        End If
    End Function


iConfig is the integer number that you want to test...
iBitToCheck is the bit position that you want to check..

Let me tell you what the expression

iConfig And (1 << (iBitToCheck - 1))

mean...
Consider iConfig = 8 and iBitToCheck = 2

first take a look at (1<<(iBitToCheck -1 ))
This will left shift 1 by (iBitToCheck-1) times...
Hence this expression becomes
(1<<(2-1))
which becomes 1<<1, which mean left shift 1 by 1..
So 1 in binary format 00000001 becomes 00000010...
left shift makes the bits to move to the left side and adds a 0 on the right hand side..

now this will be "And" ed with 8 whose binary is 00001000
Hence
00001000 And
00000010 becomes
00000000 which is integer 0 ..
so the if fails and you get the result that bit 2 of 8 is not set..

Cheers
Mohan

Note: this code is not tested for all conditions..let me know if there are bugs..


0
 
LVL 96

Assisted Solution

by:Bob Learned
Bob Learned earned 664 total points
ID: 12252795
BitVector32 class also.

Bob
0

Featured Post

How To Install Bash on Windows 10

Windows’ budding partnership with Canonical has certainly led to some great improvements. One of them being the ability to use Bash on your Windows machine without third party applications! This might be one of the greatest things a cloud engineer in a Windows environment can do!

Question has a verified solution.

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

In my previous two articles we discussed Binary Serialization (http://www.experts-exchange.com/A_4362.html) and XML Serialization (http://www.experts-exchange.com/A_4425.html). In this article we will try to know more about SOAP (Simple Object Acces…
Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
Add bar graphs to Access queries using Unicode block characters. Graphs appear on every record in the color you want. Give life to numbers. Hopes this gives you ideas on visualizing your data in new ways ~ Create a calculated field in a query: …
Do you want to know how to make a graph with Microsoft Access? First, create a query with the data for the chart. Then make a blank form and add a chart control. This video also shows how to change what data is displayed on the graph as well as form…
Suggested Courses

770 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