Modify the linked list code in Listing 5.2 (linkList2.java, LaFore book) to make it a list of objects of generic type note that each Link object contains an object of the generic type instead of a numeric value. Test your code with Personal, Book objects and integers. You need to define a class of Person which has firstname, lastname and age fields, and a class of Book which has ISBN, title and publisher fields.

Listing 5.2:

// linkList2.java // demonstrates linked list // to run this program: C>java LinkList2App //////////////////////////////////////////////////////////////// class Link { public int iData; // data item (key) public double dData; // data item public Link next; // next link in list // ------------------------------------------------------------- public Link(int id, double dd) // constructor { iData = id; dData = dd; } // ------------------------------------------------------------- public void displayLink() // display ourself { System.out.print("{" + iData + ", " + dData + "} "); } } // end class Link //////////////////////////////////////////////////////////////// class LinkList { private Link first; // ref to first link on list

// ------------------------------------------------------------- public LinkList() // constructor { first = null; // no links on list yet } // ------------------------------------------------------------- public void insertFirst(int id, double dd) { // make new link Link newLink = new Link(id, dd); newLink.next = first; // it points to old first link first = newLink; // now first points to this } // ------------------------------------------------------------- public Link find(int key) // find link with given key { // (assumes non-empty list) Link current = first; // start at 'first' while(current.iData != key) // while no match, { if(current.next == null) // if end of list, return null; // didn't find it else // not end of list, current = current.next; // go to next link } return current; // found it } // ------------------------------------------------------------- public Link delete(int key) // delete link with given key { // (assumes non-empty list) Link current = first; // search for link Link previous = first; while(current.iData != key) { if(current.next == null) return null; // didn't find it else { previous = current; // go to next link current = current.next; } } // found it if(current == first) // if first link, first = first.next; // change first else // otherwise, previous.next = current.next; // bypass it return current; } // ------------------------------------------------------------- public void displayList() // display the list { System.out.print("List (first-->last): "); Link current = first; // start at beginning of list while(current != null) // until end of list, { current.displayLink(); // print data current = current.next; // move to next link } System.out.println(""); } // ------------------------------------------------------------- } // end class LinkList //////////////////////////////////////////////////////////////// class LinkList2App { public static void main(String[] args) { LinkList theList = new LinkList(); // make list

theList.insertFirst(22, 2.99); // insert 4 items theList.insertFirst(44, 4.99); theList.insertFirst(66, 6.99); theList.insertFirst(88, 8.99);

theList.displayList(); // display list

Link f = theList.find(44); // find item if( f != null) System.out.println("Found link with key " + f.iData); else System.out.println("Can't find link");

Link d = theList.delete(66); // delete item if( d != null ) System.out.println("Deleted link with key " + d.iData); else System.out.println("Can't delete link");

theList.displayList(); // display list } // end main() } // end class LinkList2App ////////////////////////////////////////////////////////////////