Formal and Actual Parameters

Formal Parameters

Procedure declaration defines formal parameters

• general rules for every call to procedure
  • mode: in, out, in out
  • data type: integer, character, ...
  • internal name: (for use inside procedure)
• in brackets after procedure name

	    procedure adjust (
	        exam : in     INTEGER;  -- exam mark
	        mark : in out INTEGER   -- overall subject mark
	                     ) 
	    is
	        -- local declarations
	    begin
	        -- statements
	    end;

Actual Parameters

procedure call includes actual parameters

• specific parameter values for this call
• can differ for each call

examples:

	GET ( val );

	get_integer ( exam,   0, 50 );
	get_integer ( number, 1,  5 );
	get_integer ( number, low, low+4 );

	begin
	    get_exam (exam);
	    get_lab  (labs);
	    mark := exam + labs;
	    adjust (exam, mark);
	    PUT (mark);
	    print_grade (mark);
	end;