{
	When you call new(p), you are asking the operating system
	to give you a chunk of memory for your use.  When you are
	done using that memory, you should give it back to the
	operating system.  This giving back process is called "disposing"
	of the memory.
	
	To dispose of a node pointed to by a pointer p, you do this:
	
		dispose( p );
	
	Write a procedure DeleteString as described below.
	(Note that it's hard to be sure you've got this right, since
	dispose doesn't tell you anything.)
}

program copying(input,output);

type	nodePtr = ^node;

	node = record
		data : char;
		next : nodePtr
	end;

var	message : nodePtr;


{ ReadString reads characters from the keyboard until
  reaching the end of a line.  The characters are
  put into a linked list, with str pointing to the
  head of the list (which is also the first character read). }
procedure ReadString( var str : nodePtr );
var	currentNode : nodePtr;
begin
	if eoln then
		str := nil
	else
	begin
		new( currentNode );
		read( currentNode^.data );
		str := currentNode;
		
		while not eoln do
		begin
			new( currentNode^.next );
			currentNode := currentNode^.next;
			read( currentNode^.data )
		end;
		
		currentNode^.next := nil
	end
end;


{ WriteString prints a string stored as a linked list of characters. }
procedure WriteString( str : nodePtr );
var	currentNode : nodePtr;
begin
	currentNode := str;
	while currentNode <> nil do
	begin
		write( currentNode^.data );
		currentNode := currentNode^.next
	end
end;

{Dispose of the nodes in the linked list pointed to by str.}
procedure DeleteString( str : nodePtr );
begin
end;

begin
	write( 'Type something: ' );
	ReadString( message );
	write( 'You typed: ' );
	WriteString( message );
	writeln;
	DeleteString( message )
end.