Difference between revisions of "Boolean"
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'''Boolean''' is a logical datatype. Data of type boolean has one of only two values, either [[True|true]] or [[False|false]]. A Boolean variable is 1 byte in size. | '''Boolean''' is a logical datatype. Data of type boolean has one of only two values, either [[True|true]] or [[False|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 '''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. |
<syntaxhighlight> | <syntaxhighlight> |
Revision as of 09:08, 24 June 2016
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Overview
Boolean is a logical datatype. 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.
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
Ouputs:
FALSE
TRUE
FALSE
TRUE
tooLarge is true
TRUE
See also
simple data types |
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complex data types |