# Difference between revisions of "UNSIGNED"

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* [[DEFSTR]], [[DEFLNG]], [[DEFINT]], [[DEFSNG]], [[DEFDBL]] | * [[DEFSTR]], [[DEFLNG]], [[DEFINT]], [[DEFSNG]], [[DEFDBL]] |

## Latest revision as of 01:56, 20 April 2020

_UNSIGNED defines a numerical value as being only positive.

## Syntax

## Description

- Datatype can be any of the following: INTEGER, LONG, _BIT, _BYTE, _INTEGER64, _OFFSET
**SINGLE, DOUBLE and _FLOAT variable types cannot be _UNSIGNED.**- _UNSIGNED can be used in a _DEFINE statement to set undefined variable name first letters as all positive-only values.
- Can also be used in DIM statements or subprocedure parameter definitions following AS.
- _UNSIGNED allows larger positive numerical variable value limits than signed ones.
- The unsigned variable type suffix used is the
**tilde (~)**, right before the number's own type suffix:*variableName~&*

00000001 - unsigned & signed are both 1 01111111 - unsigned & signed are both 127 11111111 - unsigned is 255 but signed is -1 11111110 - unsigned is 254 but signed is -2 11111101 - unsigned is 253 but signed is -3

## Examples

*Example 1:* In **QB64**, when a signed INTEGER value exceeds 32767, the value may become a negative value:

* *
i% = 38000
PRINT i% * *

-27536

*Explanation:*Use an _UNSIGNED INTEGER or a ~% variable type suffix for only positive integer values up to 65535.

*Example 2:* In **QB64**, _UNSIGNED INTEGER values greater than 65535 cycle over again from zero:

* *
i~% = 70000
PRINT i~% * *

4464

*Explanation:*In QB64 an unsigned integer value of 65536 would be 0 with values increasing by the value minus 65536.

*Example 3:* Demonstrating how _UNSIGNED variables expand the INTEGER range.

* *
DIM n AS _UNSIGNED INTEGER
DIM pn AS _UNSIGNED INTEGER
LOCATE 3, 6: PRINT "Press Esc to exit loop"
FOR n = 1 TO 80000
_LIMIT 10000 ' 6.5 second loop
LOCATE 12, 37: PRINT n ' display current value
IF n > 0 THEN pn = n ' find highest value
IF n = 0 THEN Count = Count + 1: LOCATE 14, 37: PRINT "Count:"; Count; "Max:"; pn
IF INP(&H60) = 1 THEN EXIT FOR ' escape key exit
NEXT n
END * *

Press Esc to exit loop 65462 Count: 13 Max: 65535

*Explanation:* The maximum value can only be 65535 (32767 + 32768) so the FOR loop repeats itself. Remove the _UNSIGNED parts and run it again.

## See also

- DECLARE, SUB, FUNCTION
- DIM, _DEFINE
- DEFSTR, DEFLNG, DEFINT, DEFSNG, DEFDBL
- INTEGER, LONG, _INTEGER64
- ABS, SGN
- Variable Types

*Navigation:*