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forward Subprogram Modifier for Forward Declarations
procedure <pname>(<parameters>); forward;
function <fname>(<parameters>) : <ftype>; forward;
Occasionally, you may need to have two subprograms (procedures and
functions) call one another. However, Pascal requires that a
subprogram be declared before it can be called. FORWARD declarations
circumvent that restriction by allowing you to define a subprogram--
give its name and parameters--at one spot in your program, then
declaring it--give its actual code--later on.
-------------------------------- Example ---------------------------------
Suppose you have two subprograms, Fred and Jane, that call each other.
Here's how you might set them up:
procedure Fred(I,J : Integer; var X : Real); forward;
function Jane(A,B,C : Real) : Integer;
begin
...
Fred(5,3,A);
...
end; { of func Jane }
procedure Fred;
begin
...
J := Jane(2.3,2.9,-0.5);
...
end; { of proc Fred }
The actual declaration of Fred has no parameters; those were already
defined in the FORWARD declaration.
See Also:
procedure
function
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