DelphiBasics Boolean Type Allows just True and False values System unit

type Boolean = (False, True);

Description The Boolean type provides an enumeration of the logical True and False values.   Unlike other languages, it is not a number - it will only allow these values. This makes the code much more reliable. Notes Using calculations to test for true or false is a C like practice, but is supported in Delphi. Use the following to hold such a logical number: ByteBool WordBool LongBool Related commands And Boolean and or bitwise and of two arguments If Starts a conditional expression to determine what to do next Not Boolean Not or bitwise not of one arguments Or Boolean or or bitwise or of two arguments Xor Boolean Xor or bitwise Xor of two arguments  Download this web site as a Windows program.

Example code : Boolean assignments and tests var   same : Boolean;   small, large, i : Integer; begin   small := 23;   large := 455555;   // Test directly to see if these numbers are the same size   if small = large   then ShowMessage('small = large')   else ShowMessage('small <> large');   // Use a Boolean to hold and test this outcome   same := (small = large);   if same   then ShowMessage('small = large')   else ShowMessage('small <> large');   // Assign a direct logical value to this Boolean   same := True;   if same   then ShowMessage('same is True')   else ShowMessage('same is False'); end; Show full unit code   small <> large   small <> large   same is True

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