Using goto statements 
----------------------


read(x);
2: if x = 0 then goto 8; 
writeln(x); 
4: read(next);
   if next = x then goto 4;
   x := next;
   goto 2;
8: ; 





Using structured statements 
---------------------------

read(x);
while (x != 0) do begin 
      writeln(x);
      repeat 
	     read(next); 
      until next != x;
      x := next;
end; 



Using procedures
----------------


readentry(e);
while not endmarker(e) do begin 
      writeentry(e);
      repeat 
	     readentry(f);
      until not equalentry(e,f);
      copyentry(e,f);
end;




Single entry - single exit