Thread: Problem with binary tree

hello guys. Im trying to make a searching binary tree. i have problem with my code. i have t classes

public class BinaryTreeTest {
 
  public static void main(String[] args) {
	  BinaryNodeWithSize root = new BinaryNodeWithSize(5);
 
 
    System.out.println("Binary Tree Example");
    System.out.println("Building tree with root value " + root.value);
    BinaryNodeWithSize.insert(root, 1);
    BinaryNodeWithSize.insert(root, 8);
    BinaryNodeWithSize.insert(root, 6);
    BinaryNodeWithSize.insert(root, 3);
    BinaryNodeWithSize.insert(root, 9);
    System.out.println("Traversing tree in order");
    //BinaryNodeWithSize.printInOrder(root);
    BinaryNodeWithSize.print(root);
    Brt.size(root);
    //System.out.println("Traversing tree front-to-back from location 7");
    //BinaryNodeWithSize.printFrontToBack(root, 7);
 
 
}
}

public class BinaryNodeWithSize {
 
	BinaryNodeWithSize left;
	BinaryNodeWithSize right;
	int size;
 
    int value;
 
    public BinaryNodeWithSize(int value) {
      this.value = value;
    }
 
  public static void insert(BinaryNodeWithSize node, int value) {
    if (value < node.value) {
      if (node.left != null) {
        insert(node.left, value);
      } else {
        System.out.println("  Inserted " + value + " to left of "
            + node.value);
        node.left = new BinaryNodeWithSize(value);
      }
    } else if (value > node.value) {
      if (node.right != null) {
        insert(node.right, value);
      } else {
        System.out.println("  Inserted " + value + " to right of "
            + node.value);
        node.right = new BinaryNodeWithSize(value);
      }
    }
 
  }
 
 
  public static void printInOrder(BinaryNodeWithSize node) {
    if (node != null) {
      printInOrder(node.left);
      System.out.println("  Traversed " + node.value);
      printInOrder(node.right);
    }
  }
  public static void print(BinaryNodeWithSize node) {
	    if (node != null) {
	    	System.out.println(node.value);
	    	if (node.left != null) {
	    	System.out.println("(left child - " + node.left.value + ")");
	    	}if (node.right != null) {
	    	System.out.println("(right child - " + node.right.value + ")");
	    	}//Brt.size(node);
	    	print(node.left);
	    	print(node.right);
	    }
	  }
  /**
   * uses in-order traversal when the origin is less than the node's value
   * 
   * uses reverse-order traversal when the origin is greater than the node's
   * order
   */
  public static void printFrontToBack(BinaryNodeWithSize node, int camera) {
    if (node == null)
      return;
    if (node.value > camera) {
      // print in order
      printFrontToBack(node.left, camera);
      System.out.println("  Traversed " + node.value);
      printFrontToBack(node.right, camera);
    } else if (node.value < camera) {
      // print reverse order
      printFrontToBack(node.right, camera);
      System.out.println("  Traversed " + node.value);
      printFrontToBack(node.left, camera);
    } else {
      // order doesn't matter
      printFrontToBack(node.left, camera);
      printFrontToBack(node.right, camera);
    }
  }
 
}

its working but i want a method that can give me the depth of a node. i have try to create something like this:

public class Brt {
	int s;
	public int size(BinaryNodeWithSize node) {
	  	  if (node.left == null && node.right == null) {
	    	}
	    else if (node.left != null || node.right != null) {
	    	size(node);
	    	s+=1;
	    }return s;
	  }
}

but i get the error cannot make a static reference to a non static method size from type BinaryNodeWithSize
i have encounter this problem with insert delete etc also and thats which i made them static. can you tell where is the problem with the code? i want to be able to make non static methods and escpecially one with the size of the node.

You are trying to use the methods of BinaryNodeWithSize in a static context (eg BinaryNodeWithSize.insert()), which is why you are receiving the errors. Rather, you should be doing in the context of the object you created (eg instance methods)

BinaryNodeWithSize root = new BinaryNodeWithSize(5);
 
[COLOR="Red"]root[/COLOR].insert(root, 1);

In this way, the methods should not be static so they may refer to the object specific variables. While it doesn't have to be, the method size() can be placed within the BinaryNodeWithSize as opposed to its own class.

See Understanding Instance and Class Members (The Java™ Tutorials > Learning the Java Language > Classes and Objects) for more information