Java program to count leaves. Use the tree tester and java file provided.

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"); } }

Program.

import java.util.List; import java.util.ArrayList; /** A tree in which each node has an arbitrary number of children. Modify the Tree class to add a method that counts the number of leaves in the tree. */ 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() { //Implement the leafCount Method

int sum = 0;

if (children.size() == 0)

{

sum = 1;

}

else

{

for (Node child : children)

{

sum = sum + child.leafCount();

}

}

return sum;

}