JAVA数据结构链表

由于JAVA中没有结构体，所以必须用类来模拟，如下所示：

package LinkedList;

//linkList.java
//demonstrates linked list
//to run this program: C>java LinkListApp
////////////////////////////////////////////////////////////////
class Link {
    public int iData; // data item
    public double dData; // data item
    public Link next; // next link in list
    // -------------------------------------------------------------

    public Link(int id, double dd) // constructor
    {
        iData = id; // initialize data
        dData = dd; // ('next' is automatically
    } // set to null)
    // -------------------------------------------------------------

    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 boolean isEmpty() // true if list is empty
    {
        return (first == null);
    }

    // -------------------------------------------------------------
    // insert at start of list
    public void insertFirst(int id, double dd) { // make new link
        Link newLink = new Link(id, dd);
        newLink.next = first; // newLink --> old first
        first = newLink; // first --> newLink
    }

    // -------------------------------------------------------------
    public Link deleteFirst() // delete first item
    { // (assumes list not empty)
        Link temp = first; // save reference to link
        first = first.next; // delete it: first-->old next
        return temp; // return deleted link
    }

    // -------------------------------------------------------------
    public void displayList() {
        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
// //////////////////////////////////////////////////////////////

public class LinkListApp {
    public static void main(String[] args) {
        LinkList theList = new LinkList(); // make new list

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

        theList.displayList(); // display list

        while (!theList.isEmpty()) // until it's empty,
        {
            Link aLink = theList.deleteFirst(); // delete link
            System.out.print("Deleted "); // display it
            aLink.displayLink();
            System.out.println("");
        }
        theList.displayList(); // display list
    } // end main()
} // end class LinkListApp
// //////////////////////////////////////////////////////////////