Generate all binary string possibilities of n bits

[Renderer 1]

Hi guys! I have a question regarding binary  digits. How can I write an algorithm to generate all the possible binary combinations of n bits long? I konw the basics like 2 bit long binary strings can generate 2 ^ 2 = 4 possible combinations like 00, 01, 10, 00. How am I gonna put this into code? I really have no idea. Thanks in advance! 

[TheXman 405]

Here's one way to do it.  Note that this example will only work up to 32 bits because the AutoIt bit operations only work with 32-bit integers.  If you need to work with more bits, you will need a different solution.

display_bit_combinations(4)

Func display_bit_combinations($iNumberOfBits)
    Local $sBits = ""

    ConsoleWrite("Number of bits to display: " & $iNumberOfBits & @CRLF)

    ;Loop thru integers from 0 to 2^bits - 1
    For $i = 0 To (2 ^ $iNumberOfBits) - 1

        ;Loop thru integer's bits from high-order bit to low-order bit
        ;to build the bit string in big-endian

        $sBits = ""
        For $j = $iNumberOfBits - 1 To 0 Step -1
            $sBits &= (BitAND($i, 2 ^ $j) ? "1" : "0")
        Next

        ConsoleWrite($sBits & "b = " & $i & @CRLF)
    Next
EndFunc

Output:

Number of bits to display: 4
0000b = 0
0001b = 1
0010b = 2
0011b = 3
0100b = 4
0101b = 5
0110b = 6
0111b = 7
1000b = 8
1001b = 9
1010b = 10
1011b = 11
1100b = 12
1101b = 13
1110b = 14
1111b = 15

 

Edited November 24, 2020 by TheXman

[jchd 1,514]

Increment an integer from 0 to 2ⁿ-1

If you actually need the binary expansion in string form:

Local $n = 9
Local $s = ""
Local $aRes
Local $zeroes = _StringRepeat("0", $n - 1)
For $i = 0 To 2 ^ $n - 1
    $aRes = DllCall("ntdll.dll", "str:cdecl", "_ui64toa", "int64", $i, "str", $s, "int", 2)
    ConsoleWrite(StringRight($zeroes & $aRes[0], $n) & @LF)
Next

 

Edited November 24, 2020 by jchd

[JockoDundee 156]

Simple:

PrintBits($CmdLine[1],"")

Func PrintBits($iBits, $sBits)
   $iBits-=1
   If $iBits<0 Then
      ConsoleWrite($sBits & @CRLF)
   Else
      For $n=0 To 1
         PrintBits($iBits,$sBits & $n)
      Next
   EndIf
EndFunc

Output:

C:\>bits 4
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

C:\>

 

[JockoDundee 156]

Simpler:

PrintBits($CmdLine[1],"")

Func PrintBits($iBits, $sBits)
   If Not $iBits Then Return ConsoleWrite($sBits & @CRLF)
   PrintBits($iBits-1,$sBits & 0)
   PrintBits($iBits-1,$sBits & 1)
EndFunc

 

[Nine 992]

Even simpler :

Combine("", 4)
Func Combine($Str, $nBit)
  $t = $nBit ? Execute(Combine($Str & 0, $nbit-1) & Combine($Str & 1,$nBit-1)) : ConsoleWrite ($Str & @CRLF)
EndFunc

 

[jchd 1,514]

The recursion is nice but most users have hard time using it in the general case. Good that you posted it.

OTOH using _ui64toa allows to use any base in [2, 36] with no change (except that I did hardcore the base in the snippet). Of course, recursion can be bent to do it as well.

[JockoDundee 156]

24 minutes ago, jchd said:

The recursion is nice but most users have hard time using it in the general case.

True.
Please understand I had to post it, even if as purely a defensive measure, as I was not ready to entertain the inevitable smugness of anyone else’s recursive gloating
 

Edited November 24, 2020 by JockoDundee

[JockoDundee 156]

@Nine, assume you meant:

Combine("", 4)
Func Combine($Str, $nBit)
  $nBit ? Execute(Combine($Str & 0, $nbit-1) & Combine($Str & 1,$nBit-1)) : ConsoleWrite ($Str & @CRLF)
EndFunc

 

[Nine 992]

with :

#AutoIt3Wrapper_Run_AU3Check=n

yes. But it is one more line 

Edited November 24, 2020 by Nine

[JockoDundee 156]

16 minutes ago, Nine said:

But it is one more line 

Ah, that makes sense.  I don’t use Scite much, just the compiler, and it doesn’t complain.  Come to think of it, the compiler doesn’t complain about anything really, as long as for every <tag> there’s a </tag>.

Anyway, if you want a real challenge - https://www.autoitscript.com/forum/topic/204426-guess-the-output/