Difference between revisions of "Case"

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Line 26: Line 26:
 
  begin
 
  begin
 
   s := '';
 
   s := '';
   case c of
+
   case s of
 
     '0' .. '9' : s := 'digit (0-9)';
 
     '0' .. '9' : s := 'digit (0-9)';
 
     'a' .. 'z' : s := 'small letter (a-z)';
 
     'a' .. 'z' : s := 'small letter (a-z)';

Revision as of 17:45, 17 October 2010

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Case opens a case statement. The case statement compares the value of ordinal expression to each selector, which can be a constant, a subrange, or a list of them separated by commas. Selector field separated from action field by Colon.

The case statement includes reserved words Of and End . Sometimes Else, too.


<delphi>

case place of
  1: ShowMessage('Gold medal');
  2: ShowMessage('Silver medal');
  3: ShowMessage('Bronze medal'); 
  else ShowMessage('Better luck next time'); 
end;

</delphi>

WhatIsChar

<delphi>

function WhatIsChar( c:char ):string;
var
  s : string;
begin
  s := ;
  case s of
    '0' .. '9' : s := 'digit (0-9)';
    'a' .. 'z' : s := 'small letter (a-z)';
    'A' .. 'Z' : s := 'big letter (A-Z)';
    '+' , '-'  : s := 'sign (+ or -)';
  end;
  result := s;
end;

</delphi>

Variant Record

Case-word is used Variant Record, too. Variant Record also called a tagged union.

<delphi>

 type
     
  ScaleKelvin = 223 .. 323;
  ScaleCelsius = -50 .. 50;
   
  TemperatureScale   =  ( celcius, kelvin ) ;
  Temperature   =   record
   case  scale   :   TemperatureScale   of
    celcius : (celcius_value : ScaleCelsius);
    kelvin : (kelvin_value : ScaleKelvin);
  end;

</delphi>

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