Micheal Kenny

How can I get my showAll() method to print out all student records because as it stands it only print out one student record and the rest of the records are printed as null which is not what I want. Also, how can I get my fetch method to actually print a student record based on just the string parameter I input into that method. Here is my code so far.

public class Listing implements Comparable<Listing> { private String name;  // key field  private int ID;   private double GPA;  public Listing(String n, int id, double gpa)  {  name = n;      ID = id;     GPA = gpa;  }   public String toString()   {   return("Name is " + " "  + name +                    "\nID is" + " " + ID +                    "\nGPA is" + " "  + GPA + "\n");   }   public Listing deepCopy()   {  Listing clone = new Listing(name, ID, GPA);      return clone;   }   public int compareTo(Listing other)   {       return this.name.compareTo(other.getKey());   }   public int compareTo(String targetKey)   {       return (name.compareTo(targetKey));   }   public String getKey()   {       return name;   } }// end of class Listing

public class BinaryTreeArray 02 { 03   private Listing[] data; 04   private int size; 05   private int i = 0; 06 07  public BinaryTreeArray() 08  { 09      size = 100; 10      data = new Listing[size]; 11  } 12  public boolean insert(Listing newListing) 13  { 14     while(i < size && data[i]!= null) 15     { 16       if(data[i].getKey().compareTo(newListing.getKey()) > 0) 17         i = 2 * i + 1; 18        else 19         i = 2 * i + 2; 20     } 21     if(i >= size) 22       return false; 23     else 24     { 25         data[i] = newListing.deepCopy(); 26          return true; 27      } 28  } 29  public Listing fetch(String targetKey) 30  { 31    while(i< size && data[i]!= null && data[i].getKey()!=targetKey) 32    { 33        if(data[i].getKey().compareTo(targetKey) > 0) 34          i = 2 * i + 1; 35       else 36          i = 2 * i + 2;   37    } 38    if(i >= size || data[i] == null) 39      return null; 40    else 41      return data[i].deepCopy(); 42  } 43 44 }

mport java.util.Scanner; 02 03 04 public class MainBinaryTreeArray 05 { 06  public static void main(String[] args) 07  { 08 09     int choice; 10     Scanner scan= new Scanner(System.in); 11     BinaryTreeArray data = new BinaryTreeArray(); 12     Listing l1  = new Listing("Carol",    4354,  3.2); 13     Listing l2  = new Listing("Timothy",  2353,  4.0); 14     Listing l3  = new Listing("Dean",     4544,  2.4); 15     Listing l4  = new Listing("Sue",      3445,  3.0); 16   17 18   do 19   { 20 21       // Choose which operation by entering a number 22 23      System.out.println("*****************(Menu Operations:)******************"); 24      System.out.println(" (Press 1). Insert."); 25      System.out.println(" (Press 2). Fetch."); 26      System.out.println(" (Press 5). Output."); 27      System.out.println(" (Press 6). Exit the program."); 28      System.out.println("Enter your choice: "); 29      choice = scan.nextInt(); 30      switch(choice) 31      { 32        case 1: 33             System.out.println("Is a student's info inserted: " + data.insert(l1)); 34           break; 35        case 2: 36         System.out.println("Is a student's info fetched: "  + data.fetch("Timothy")); 37           break; 38        case 5: 39            System.out.println("The student's info that is output: " + l4.toString()); 40      } 41   42   43  }while(choice!=6); 44 45 } 46 47 }

If I have binary search tree data structure, how could implement as a linked based structure with the  code I have below ( I am open to all suggestions!):

public class Node {    public int Data;    public Node Left;    public Node Right;    public void DisplayNode() {      Console.Write(Data + " ");    }  }    public class BinarySearchTree {    public Node root;    public BinarySearchTree() {      root = null;    }    public void Insert(int i) {      Node newNode = new Node();      newNode.Data = i;      if (root == null)        root = newNode;      else {        Node current = root;        Node parent;        while (true) {           parent = current;           if (i < current.Data) {              current = current.Left;              if (current == null) {                 parent.Left = newNode;                 break;              }        else {             current = current.Right;             if (current == null) {                parent.Right = newNode;                break;         }       }     }   } }