Interrogating a binary value in an integer

  • Thread starter Thread starter BobRoyAce
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BobRoyAce

I have a third party user control that contains 7 checkedits, one for
each day of the week. It stores which days are checked as an integer
by adding up the values for each day checked, using the following
values:

SUN 1
MON 2
TUE 4
WED 8
THU 16
FRI 32
SAT 64

So, for example, if TUE, WED, & THU are the only days checked, it
stores a value of 28. If FRI, SAT, & SUN only, it stores a value of
97.

How can I interrogate the integer value to know if a particular day
was checked? In other words, if I knew that the integer value was 28,
what calculation/operation would I perform on that number to determine
that, yes, it does indicate that THU was checked? Or, if the value was
96, I could determine that no, THU was not checked?
 
BobRoyAce said:
I have a third party user control that contains 7 checkedits, one for
each day of the week. It stores which days are checked as an integer
by adding up the values for each day checked, using the following
values:

SUN 1
MON 2
TUE 4
WED 8
THU 16
FRI 32
SAT 64

So, for example, if TUE, WED, & THU are the only days checked, it
stores a value of 28. If FRI, SAT, & SUN only, it stores a value of
97.

How can I interrogate the integer value to know if a particular day
was checked? In other words, if I knew that the integer value was 28,
what calculation/operation would I perform on that number to determine
that, yes, it does indicate that THU was checked? Or, if the value was
96, I could determine that no, THU was not checked?
Click to expand...

You can use AND operator to check this. Here is a small example:

Dim tb As New System.Text.StringBuilder
Dim value As Integer = 97

Dim i As Integer = 0

While 2 ^ i < 128

tb.AppendLine(i.ToString + " " + CStr((value And 2 ^ i) = 2 ^
i))
i += 1

End While

TextBox1.Text = tb.ToString

-Teemu
 
Teemu said:
You can use AND operator to check this. Here is a small example:

Dim tb As New System.Text.StringBuilder
Dim value As Integer = 97

Dim i As Integer = 0

While 2 ^ i < 128

tb.AppendLine(i.ToString + " " + CStr((value And 2 ^ i) = 2 ^
i))
i += 1

End While

TextBox1.Text = tb.ToString
Click to expand...

Maybe this was a bad example. If you want to know does 97 contain THU, just
check if (97 And 16)=16.

-Teemu
 
BobRoyAce said:
I have a third party user control that contains 7 checkedits, one for
each day of the week. It stores which days are checked as an integer
by adding up the values for each day checked, using the following
values:

SUN 1
MON 2
TUE 4
WED 8
THU 16
FRI 32
SAT 64

So, for example, if TUE, WED, & THU are the only days checked, it
stores a value of 28. If FRI, SAT, & SUN only, it stores a value of
97.

How can I interrogate the integer value to know if a particular day
was checked?
Click to expand...

const sun as integer = 1
const thur as integer = 16
const sat as integer = 64

dim tday as integer

tday = 28

if tday AND thurs then

end if
 
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