Reference parameter passing (extracted from Delphi basic)

		Passing by reference means that the subroutine actually refers to the passed variable rather than its value. Any changes to the value will affect the caller variable.We declare a variable to be passed by reference withVaRPrefix. rewriting the above Code to use by reference changes matters:
		procedure doit (var a: integer); begin : = A * 2; showmessagefmt ('a in the procedure = % d', [a]); end; procedure tform1.formcreate (Sender: tobject ); var A: integer; begin A: = 22; showmessagefmt ('a in program before call = % d', [a]); // call the procedure doit (); showmessagefmt ('a in program now = % d', [a]); end;
		A In program before call = 22 A In the procedure = 44 A In program now = 44
		Now the callerAVariable is updated by the procedure.
		This is a very useful way of returning data from a procedure, as used by, for example, the Delphi insert routine. It also allows us to return more than one value from a subroutine.