while boolean_expression do statement
The while statement declares a loop. For further description see while Statement.
while is defined in ISO 7185 Pascal and supported by all known Pascal variants.
program WhileDemo; var Foo, Bar: Integer; begin WriteLn ('Enter an descending series of integer numbers.'); WriteLn ('Terminate by breaking this rule.'); WriteLn ('Enter start number: '); Bar := MaxInt; ReadLn (Foo); while Foo < Bar do begin Bar := Foo; ReadLn (Foo) end; WriteLn ('The last number of your series was: ', Bar) end.