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.