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{{DISPLAYTITLE:_FLOAT}} | {{DISPLAYTITLE:_FLOAT}} | ||
'''_FLOAT''' numerical values | '''_FLOAT''' variables are 80-bits floating point numerical values up to nineteen digits precision ([[Wikipedia:Extended_precision|see IEEE 754 Extended precision]]). This variable type is new to QB64(PE), it is not available in QuickBASIC/QBasic. | ||
{{PageSyntax}} | {{PageSyntax}} | ||
::[[DIM]] {{Parameter|variable}} AS [[_FLOAT]] | ; Explicit declaration | ||
: [[DIM]] {{Parameter|variable}} [[AS]] [[_FLOAT]] 'AS type variant | |||
: [[DIM]] {{Parameter|variable}}## 'type suffix variant ('''##''') | |||
; Implicit for a specific letter range | |||
: [[_DEFINE]] F-G [[AS]] [[_FLOAT]] 'all variables beginning with F(f) or G(g) | |||
; Implicit without declaration | |||
: {{Parameter|variable}}## 'simply always use the type suffix | |||
; {{Text|'''Note'''|red}} | |||
:* Although the numbers are 80-bits wide (10 bytes), QB64(PE) always allocates 32 bytes to store this value. | |||
{{PageDescription}} | {{PageDescription}} | ||
* ''' | * Values can range up to 19 digits. Decimal point accuracy depends on whole value places taken. | ||
* The suffix '''##''' can also be placed after a literal numerical value to designate the value as '''_FLOAT'''. | |||
* Values may be given as real number (''123.456'') or scientific notation using '''F''' as exponent marker (''1.23456F+2''). | |||
* [[PRINT]] usually takes the shorter of both notations (depending on the value) to output the numbers. In alternative you may use [[PRINT USING]] to designate your desired output format. | |||
* Values | |||
* Floating decimal point numerical values cannot be [[_UNSIGNED]]. | * Floating decimal point numerical values cannot be [[_UNSIGNED]]. | ||
* Values can be converted to 32 | * Values can be converted to 32-bytes [[STRING]] values using [[_MK$]]('''_FLOAT''', value) and back to numbers with [[_CV]]('''_FLOAT''', value$). | ||
* ''' | ; Some useful [[constants]] are available since QB64-PE v4.0.0 | ||
:* _SIZE_OF_FLOAT = 32 'in bytes | |||
:* _FLOAT_MIN## = -1.189731495357231765F+4932 'smallest normal number | |||
:* _FLOAT_MAX## = 1.189731495357231765F+4932 'largest normal number | |||
:* _FLOAT_MIN_FRAC## = 3.362103143112093506F-4932 'smallest normal number closest to zero | |||
{{PageAvailability}} | |||
<!-- QB64 = a version or none, QBPE = a version or all, Platforms = yes or no --> | |||
<gallery widths="48px" heights="48px" mode="nolines"> | |||
File:Qb64.png|'''all''' | |||
File:Qbpe.png|'''all''' | |||
File:Apix.png | |||
File:Win.png|'''yes''' | |||
File:Lnx.png|'''yes''' | |||
File:Osx.png|'''yes''' | |||
</gallery> | |||
<!-- additional availability notes go below here --> | |||
* In all '''QB64(PE)''' versions there's the problem, that [[STR$]] can't correctly handle values exceeding the [[DOUBLE]] range. This unfortunatly also affects the [[PRINT]] output. | |||
* Since '''QB64-PE v4.0.0''' the [[_TOSTR$]] function can be used, if the entire '''_FLOAT''' range must be covered. However, this doesn't fix the [[PRINT]] issue, hence you must first convert the number and then print the string instead. | |||
{{PageSeeAlso}} | {{PageSeeAlso}} | ||
* [[DOUBLE]], [[ | * [[SINGLE]], [[DOUBLE]] | ||
* [[DIM]], [[_DEFINE]] | |||
* [[_MK$]], [[_CV]] | * [[_MK$]], [[_CV]] | ||
* [[ | * [[LEN]], [[Constants]] | ||
* [[Variable Types]] | * [[Variable Types]] | ||
{{PageNavigation}} | {{PageNavigation}} | ||
Revision as of 14:20, 25 December 2024
_FLOAT variables are 80-bits floating point numerical values up to nineteen digits precision (see IEEE 754 Extended precision). This variable type is new to QB64(PE), it is not available in QuickBASIC/QBasic.
Syntax
- Explicit declaration
- DIM variable AS _FLOAT 'AS type variant
- DIM variable## 'type suffix variant (##)
- Implicit for a specific letter range
- _DEFINE F-G AS _FLOAT 'all variables beginning with F(f) or G(g)
- Implicit without declaration
- variable## 'simply always use the type suffix
- Note
-
- Although the numbers are 80-bits wide (10 bytes), QB64(PE) always allocates 32 bytes to store this value.
Description
- Values can range up to 19 digits. Decimal point accuracy depends on whole value places taken.
- The suffix ## can also be placed after a literal numerical value to designate the value as _FLOAT.
- Values may be given as real number (123.456) or scientific notation using F as exponent marker (1.23456F+2).
- PRINT usually takes the shorter of both notations (depending on the value) to output the numbers. In alternative you may use PRINT USING to designate your desired output format.
- Floating decimal point numerical values cannot be _UNSIGNED.
- Values can be converted to 32-bytes STRING values using _MK$(_FLOAT, value) and back to numbers with _CV(_FLOAT, value$).
- Some useful constants are available since QB64-PE v4.0.0
-
- _SIZE_OF_FLOAT = 32 'in bytes
- _FLOAT_MIN## = -1.189731495357231765F+4932 'smallest normal number
- _FLOAT_MAX## = 1.189731495357231765F+4932 'largest normal number
- _FLOAT_MIN_FRAC## = 3.362103143112093506F-4932 'smallest normal number closest to zero
Availability
all
all
yes
yes
yes
- In all QB64(PE) versions there's the problem, that STR$ can't correctly handle values exceeding the DOUBLE range. This unfortunatly also affects the PRINT output.
- Since QB64-PE v4.0.0 the _TOSTR$ function can be used, if the entire _FLOAT range must be covered. However, this doesn't fix the PRINT issue, hence you must first convert the number and then print the string instead.
See also