Difference between revisions of "Boolean"
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− | Boolean | + | {{Boolean}} |
+ | |||
+ | == Overview == | ||
+ | The [[simple type]] '''boolean''' is a logical [[Data_type|data type]]. Data of type boolean has one of only two values, either [[True|<code>true</code>]] or [[False|<code>false</code>]]. A boolean [[Variable|variable]] is 1 byte in size. | ||
+ | |||
+ | The <code>true</code> value can be assigned directly to a boolean variable or from the result of a comparison or test that was successful (<code>true</code>). Similarly the <code>false</code> value can be assigned directly or from the result of a comparison or test that was not successful (<code>false</code>). | ||
+ | The [[Write]]() and Writeln() [[Procedure|procedures]] will print a [[String|string]] that corresponds to the value of a boolean variable (either "TRUE" or "FALSE"). A Boolean variable can be used as the expression in an [[If|if statement]]. The WriteStr() procedure can be used to store a string literal representing a boolean variable's value in a string variable. | ||
+ | |||
+ | <syntaxhighlight lang=pascal> | ||
+ | program booleantest; | ||
+ | var | ||
+ | tooLarge : Boolean = false; | ||
+ | boolString : ShortString; | ||
+ | begin | ||
+ | Writeln(tooLarge); | ||
+ | tooLarge := (0 = 0); | ||
+ | Writeln(tooLarge); | ||
+ | tooLarge := (3 > 5); | ||
+ | Writeln(tooLarge); | ||
+ | tooLarge := true; | ||
+ | Writeln(tooLarge); | ||
+ | if tooLarge then | ||
+ | Writeln('tooLarge is true') | ||
+ | else | ||
+ | Writeln('tooLarge is false'); | ||
+ | WriteStr(boolString,tooLarge); | ||
+ | Writeln(boolString); | ||
+ | end. | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Outputs:<br/> | ||
+ | '''FALSE''' | ||
+ | '''TRUE''' | ||
+ | '''FALSE''' | ||
+ | '''TRUE''' | ||
+ | '''tooLarge is true''' | ||
+ | '''TRUE''' | ||
+ | |||
+ | == See also == | ||
+ | * [[Boolean Expressions]] | ||
+ | |||
+ | {{Data types}} |
Latest revision as of 10:17, 14 October 2020
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Overview
The simple type boolean is a logical data type. Data of type boolean has one of only two values, either true
or false
. A boolean variable is 1 byte in size.
The true
value can be assigned directly to a boolean variable or from the result of a comparison or test that was successful (true
). Similarly the false
value can be assigned directly or from the result of a comparison or test that was not successful (false
).
The Write() and Writeln() procedures will print a string that corresponds to the value of a boolean variable (either "TRUE" or "FALSE"). A Boolean variable can be used as the expression in an if statement. The WriteStr() procedure can be used to store a string literal representing a boolean variable's value in a string variable.
program booleantest;
var
tooLarge : Boolean = false;
boolString : ShortString;
begin
Writeln(tooLarge);
tooLarge := (0 = 0);
Writeln(tooLarge);
tooLarge := (3 > 5);
Writeln(tooLarge);
tooLarge := true;
Writeln(tooLarge);
if tooLarge then
Writeln('tooLarge is true')
else
Writeln('tooLarge is false');
WriteStr(boolString,tooLarge);
Writeln(boolString);
end.
Outputs:
FALSE TRUE FALSE TRUE tooLarge is true TRUE
See also
simple data types |
|
---|---|
complex data types |