Creating Insert Method for a binary tree

I have code for a binary tree http://sourcepost.sytes.net/sourceview.aspx?source_id=5046
I'm trying to create an insert method that will accept an element and insert it into my binary tree. The main purpose of this is to test my traversal functions, intrav(), postrav(), pretrav(). I have another class that will create 10 random numbers and call insert() to insert them into my tree. Can anyone help me write this method?

anyone?

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DaDonYordel wrote:
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commit;
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DECLARE
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ORA-06512: at "RAS4.PERSON_TP", line 7
ORA-06512: at line 12
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PN,
First, it's impossible to create static method with WD IDE designers for controllers.
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http://www.NetWeaverTeam.com

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           of the binary tree. The line "null" indicates a null tree.
      @param bR The input file
      @return The binary tree
      @throws IOException If there is an input error
public static BinaryTree<String> readBinaryTree(BufferedReader bR) throws IOException
    // Read a line and trim leading and trailing spaces.
    String data = bR.readLine().trim();
    if (data.equals("null")) {
      return null;
    else {
      BinaryTree < String > leftTree = readBinaryTree(bR);
      BinaryTree < String > rightTree = readBinaryTree(bR);
      return new BinaryTree < String > (data, leftTree, rightTree);
}//readBinaryTree()
/*Method to determine the height of a binary tree
    pre: The line "null" indicates a null tree.
      @param T The binary tree
      @return The height as integer
public static int height(BinaryTree T){
      if(T == null){
           return 0;
      }else{
           return 1 +(int) (Math.max(height(T.getRightSubtree()), height(T.getLeftSubtree())));
public static String preOrderTraversal(BinaryTree<String> T){
      String s = T.toString();
      String s2 = "";
      String temp = "";
      Scanner scan = new Scanner(s);
      while(scan.hasNextLine()){
           temp = scan.nextLine().trim();
           if(temp.equals("null")){
               s2 = s2;
          }else{
               s2 = s2 + " " + temp;
      return s2;
}//class BinaryTree

As well as warnerja's point, you say you keep getting these errors. Sometimes it's helpful when illustrating a problem to replace the file based input with input that comes from a given String. That way we all see the same behaviour under the same circumstances.
public static void main(String[] args) throws FileNotFoundException, IOException{
    //Scanner scan = new Scanner(new FileReader("encode.in.txt"));
    Scanner scan = new Scanner("whatever");The following isn't the cause of an NPE, but it might be allowing one to "slip through" (ie you think you've dealt with the null case when you haven't):
public static String decode(Character c) throws IOException{
    if(c.equals("null")){
c is a Character so it will never be the case that it is equal to the string n-u-l-l.
Perhaps the behaviour of each of these methods needs to be (documented and) tested.

Creating Insert Method for a binary tree

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