QB64-PE/internal/help/AND.txt

The logical [[AND]] numerical operator compares two values in respect of their bits. If both bits at a certain position in both values are set, then that bit position is set in the result.


{{PageSyntax}}
:{{Parameter|result}} = {{Parameter|firstvalue}} AND {{Parameter|secondvalue}}


{{PageDescription}}
* [[AND]] compares the bits of the {{Parameter|firstvalue}} against the bits of the {{Parameter|secondvalue}}, the result is stored in the {{Parameter|result}} variable.
* If both bits are on (1) then the result is on (1).
* All other conditions return 0 (bit is off).
* AND is often used to see if a bit is on by comparing a value to an exponent of 2.
* Can turn off a bit by subtracting the bit on value from 255 and using that value to AND a byte value.


{{Template:LogicalTruthTable}}


{{PageExamples}}
''Example 1:''
{{WhiteStart}}
         101
         AND
         011
        -----
         001
{{WhiteEnd}}

:The 101 bit pattern equals 5 and the 011 bit pattern equals 3, it returns the bit pattern 001 which equals 1. Only the Least Significant Bits (LSB) match. So decimal values 5 AND 3 = 1.


''Example 2:''
{{WhiteStart}}
      11111011
        AND
      11101111
     ----------
      11101011
{{WhiteEnd}}
:Both bits have to be set for the resulting bit to be set. You can use the [[AND]] operator to get one byte of a two byte integer this way:

::firstbyte = twobyteint AND 255

:Since 255 is 11111111 in binary, it will represent the first byte completely when compared with AND.

:To find the second (HI) byte's decimal value of two byte [[INTEGER]]s use: secondbyte = twobyteint \ 256


''Example 3:'' Finding the binary bits on in an [[INTEGER]] value. 
{{CodeStart}}

 DO
  {{Cl|INPUT}} "Enter Integer value from -32768 to 32767 (Enter quits): ", INTvalue& 
  IF INTvalue& < -32768 OR INTvalue& > 32767 OR INTval& = 0 THEN {{Cl|EXIT DO}}
  {{Cl|FOR...NEXT|FOR}} exponent = 15 {{Cl|TO}} 0 {{Cl|STEP}} -1
    {{Cl|IF...THEN|IF}} (INTvalue& {{Cl|AND}} 2 ^ exponent) {{Cl|THEN}} {{Cl|PRINT}} "1"; {{Cl|ELSE}} {{Cl|PRINT}} "0";
  {{Cl|NEXT}}
  PRINT " "
 LOOP UNTIL INTvalue& = 0 'zero entry quits

{{CodeEnd}}

:Example output for 6055.
{{OutputStart}}
0001011110100111
{{OutputEnd}}
::''Note:'' The value of 32767 sets 15 bits. -1 sets all 16 bits. Negative values will all have the highest bit set. Use [[LONG]] variables for input values to prevent overflow errors.


{{PageSeeAlso}}
* [[OR]], [[XOR]], [[NOT]] {{text|(logical operators)}}
* [[AND (boolean)]]
* [[Binary]], [[Boolean]]


{{PageNavigation}}
<