Difference between revisions of "Constant"

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{{Constant}}
 
{{Constant}}
  
A '''constant''' is a variable that does not change, it has a final value.
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A '''constant''' is a [[Variable|variable]] that does not change, it has a final value.
  
Constants are defined in the [[Const#Const_Section|<code>const</code> section]] of a Free Pascal program. When a symbol is defined as constant, the [[Compiler|Free Pascal compiler]] can often do some optimizations to make the output code faster or smaller.
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Constants are defined in the [[Const#Const_Section|<code>const</code> section]] of a [[FPC|Free Pascal]] [[Program|program]]. When a symbol is defined as constant, the [[Compiler|Free Pascal compiler]] can often do some optimizations to make the output code faster or smaller.
  
  
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data type limits
 
data type limits
* [[Nil|<syntaxhighlight lang="pascal" enclose="none">nil</syntaxhighlight>]]: empty pointer value
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* [[Nil|<syntaxhighlight lang="pascal" enclose="none">nil</syntaxhighlight>]]: empty [[Pointer|pointer]] value
 
* [[maxint|<syntaxhighlight lang="pascal" enclose="none">maxint</syntaxhighlight>]]: largest possible [[Integer|<syntaxhighlight lang="pascal" enclose="none">integer</syntaxhighlight>]] value
 
* [[maxint|<syntaxhighlight lang="pascal" enclose="none">maxint</syntaxhighlight>]]: largest possible [[Integer|<syntaxhighlight lang="pascal" enclose="none">integer</syntaxhighlight>]] value
  
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The mathematical value [[Pi|π]] is realized as a function in {{Doc|package=RTL|unit=system|identifier=pi|text=<syntaxhighlight lang="pascal" enclose="none">system.pi</syntaxhighlight>}}.
 
The mathematical value [[Pi|π]] is realized as a function in {{Doc|package=RTL|unit=system|identifier=pi|text=<syntaxhighlight lang="pascal" enclose="none">system.pi</syntaxhighlight>}}.
  
== see also ==
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== See also ==
 
* [[Const|<syntaxhighlight lang="pascal" enclose="none">const</syntaxhighlight>]]
 
* [[Const|<syntaxhighlight lang="pascal" enclose="none">const</syntaxhighlight>]]
 
* [[Constants]]
 
* [[Constants]]
 
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* [[Class constants]]
[[Category:Constants]]
 
[[Category:Pascal]]
 

Latest revision as of 08:15, 9 August 2020

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A constant is a variable that does not change, it has a final value.

Constants are defined in the const section of a Free Pascal program. When a symbol is defined as constant, the Free Pascal compiler can often do some optimizations to make the output code faster or smaller.


Some special Free Pascal constants are:

Logical truth values

data type limits


The mathematical value π is realized as a function in system.pi.

See also