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Table of Contents
2. TMT Pascal Language Description
2.2. Pascal Language Structure
2.2.9. Statements
2.2.9.3. Case Statement
2.2.9.3. Case Statement
The case statement selects from a list of statements basing
it's decision on the value of an expression. case statements
take the following form:
case expression of
Selector : statement
[else statement]
end;
where expression is a value of ordinal type. The case expression
value is matched against each Selector. If a match exists the
statement following the matching Selector is executed.
Control is then transferred out of the case.
If no Selector matches the case expression then control is
passed to an optional else clause. Selector must evaluate to a
constant at compile time and is defined as:
expression [..expression] [,expression [..expression]]}
If .. is specified followed by another expression the case
applies to the entire range between the first expression and the second
expression. The following is an example of the case statement:
case Int of
5 : WriteLn('Int is 5');
7..12,15: WriteLn('Between 7..12 or 15');
else
begin
WriteLn('Undefined.');
GetNextInt;
end;
end;
Performance for large case statements improves if the most common
subcases are listed first.
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