Modern Math AbsChecked

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AbsChecked

Returns the absolute value as an Optional, empty for the most negative value.

Syntax

AbsChecked( byval a as T ) as Optional( of T )

Notes

• There is exactly one failing case, and it is the reason this exists: the most negative value of a two's-complement type has no positive counterpart. abs( -128 ) on a BYTE is -128.
• Every other input returns its magnitude.
• AbsSaturating clamps that one case to the maximum instead.

Examples

#import "std/numeric"
using numeric

dim as int8 worst = -128

var r = AbsChecked( worst )
print r.HasValue( )          '' false -- there is no +128 in a BYTE

'' Which is what the bare operator gets silently wrong
print abs( worst )           '' -128

dim as int8 ordinary = -5
print AbsChecked( ordinary ).Value( )         '' 5

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Library: Math Library
Category: Math Library
Documented under: Members