A Practical Introduction to Data Structures and Algorithm Analysis

108 Chap. 4 Lists, Stacks, and Queuesclass Link {private E element;private Link next;// Singly linked list node// Value for this node// Pointer to next node in list// ConstructorsLink(E it, Link nextval){ element = it; next = nextval; }Link(Link nextval) { next = nextval; }Link next() { return next; }Link setNext(Link nextval){ return next = nextval; }E element() { return element; }E setElement(E it) { return element = it; }} // class LinkFigure 4.4 A simple singly linked list node implementation.headcurrtailhead20 23 12 15(a)currtail2023101215(b)Figure 4.5 Illustration of a faulty linked-list implementation where curr pointsdirectly to the current node. (a) Linked list prior to inserting element withvalue 10. (b) Desired effect of inserting element with value 10.of the list. The position of the current element is indicated by another pointer,named curr. Finally, because there is no simple way to compute the length of thelist simply from these three pointers, the list length must be stored explicitly, andupdated by every operation that modifies the list size. The value cnt stores thelength of the list.Note that LList’s constructor maintains the optional parameter for minimumlist size introduced for Class AList. This is done simply to keep the calls to theconstructor the same for both variants. Because the linked list class does not needto declare a fixed-size array when the list is created, this parameter is unnecessaryfor linked lists. It is ignored by the implementation.