98  Pascal User Manual  A variable of type  Link, called Fi [st, points to the first person of the  list. The Next field of the last person in the list is  ni 1. Note in passing  that  points to the third person in the list  If we assume that, for example, we  can read  integer data representing the  heights of people, then the  following code could have been  u~ed  to construct the above chain.  Firstl.Nextl.Next  Note that the list grows backwards. For purposes of access, we will  introduce another variable, say  Pt, I)f type Link and allow it to move  freely through the list. To demons!)  :Ite  selection, we assume there is a  Person  with Height  equal to  1  "  and access this Person. The  strategy is to advance  Pt via Link itntil the desired person is located:  In words this says, "Let Pt point to the first person. While the height of  the person pointed to (identified) by Pt  is not 175, assign to Pt  the  pointer value stored in the  Next  field (also a pointer variable) of the  record that  Pt currently identifies."  Pt  := First;  while Ptl.Height  <>  175L, Pt  := Ptl.Next  var First,  P:  Link;  H,':  Integer;  First  := nil;  for  I  :=  1  to N do  begin Read(H);  New(l);  pI.Next  := First;  end  pI.Height  := H;  ],itializeOtherFields(PI);  First  .- P  Figure 10.c  Linked List  Person  Person  A linked list of  n  persons can be represented as in Figure 10.c. Each  box represents one person. 