Difference between revisions of "Constant"
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Jump to navigationJump to search (New page: A '''constant''' is something that does not change, a fixed value. Constants are defined in the const section of the program. When some value are constant the [[Compiler|compile...) |
(→See also: Add link to Class Constants) |
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| − | + | {{Constant}} | |
| − | + | 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 [[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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| − | Some special | + | Some special Free Pascal constants are: |
| − | + | Logical truth values | |
| + | * [[False|<syntaxhighlight lang="pascal" enclose="none">false</syntaxhighlight>]] | ||
| + | * [[True|<syntaxhighlight lang="pascal" enclose="none">true</syntaxhighlight>]] | ||
| − | * [[ | + | data type limits |
| + | * [[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 | ||
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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>}}. | |
| − | * [[ | + | == See also == |
| − | + | * [[Const|<syntaxhighlight lang="pascal" enclose="none">const</syntaxhighlight>]] | |
| − | + | * [[Constants]] | |
| − | + | * [[Class constants]] | |
| − | * [[ | ||
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.
