Program to count leaves. Use the tree tester.

public class TreeTester { public static void main(String[] args) { Tree t1 = new Tree("Anne"); Tree t2 = new Tree("Peter"); t1.addSubtree(t2); Tree t3 = new Tree("Zara"); t1.addSubtree(t3); Tree t4 = new Tree("Savannah"); t2.addSubtree(t4); System.out.println("Size: " + t1.size()); System.out.println("Expected: 4"); System.out.println("Leaf count: " + t1.leafCount()); System.out.println("Expected: 2"); } }

My program is below but i have errors. Please help to rectify. Thanks

import java.util.List;

import java.util.ArrayList;

/**

add a method that counts the number of leaves in the tree. The error is at leafcount

*/

public class Tree

{

private Node root;

class Node

{

public Object data;

public List children;

/**

Computes the size of the subtree whose root is this node.

@return the number of nodes in the subtree

*/

public int size()

{

int sum = 0;

for (Node child : children) { sum = sum + child.size(); }

return 1 + sum;

}

}

/**

Constructs an empty tree.

*/

public Tree()

{

root = null;

}

/**

Constructs a tree with one node and no children.

@param rootData the data for the root

*/

public Tree(Object rootData)

{

root = new Node();

root.data = rootData;

root.children = new ArrayList<>();

}

/**

Adds a subtree as the last child of the root.

*/

public void addSubtree(Tree subtree)

{

root.children.add(subtree.root);

}

/**

Computes the size of this tree.

@return the number of nodes in the tree

*/

public int size()

{

if (root == null) { return 0; }

else { return root.size(); }

}

public int leafCount()

{

int sum = 0;

if (children.size() == 0)

{

sum = 1;

}

else

{

for (Node child : children)

{

sum = sum + child.leafCount();

}

}

return sum;

public static int leafCount(Node child)

{

//Implement the leafCount Method

if (child == null)

return 0;

if (child.left==null) and (child.right==null)

return 1;

else

return leafCount(n.left)+leafCount(n.right);

}

}