Hello,
Two basic questions about pointer targets (I call target what is pointed to).
-1- untyped pointer allocation
In case of an untyped pointer, I read the compiler considers the target'size is
1 byte. There certainly is an operation to allocate memory for the target
according to an existing piece of data. Something like
data := something
new(p,data);
// Either p points to data where it was
// or a new memory area is silently reserved,
// data copied there, and p holds its address.
-2- reflexive pointing
The following works, but I do not understand how.
======= code =======
program LinkedList;
uses
Classes, SysUtils; //, Variants;
// typed list version
type
List = ^Node;
Node = record
next : List;
data : ^Integer;
end;
var
endNode : List;
procedure defineEndNode();
begin
new(endNode);
with endNode^ do begin
new(data);
data^ := 0;
next := endNode;
end;
end;
//[...]
begin
// end node flag
defineEndNode();
writeln(endNode^.data^);
//[...]
end.
======= /code ======
The issue is: ^endNode holding a pointer to endNode, how is this kind of
infinite self-referencing loop resolved by the compiler, at definition time?
PS: How else terminate a linked list in Pascal? (I must put something in the
.next field of the last actual node, and this thing must be a List, ie a node
pointer.)
Denis
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