implemented clearTree and treeSize functions

bintree.c

@@ -26,11 +26,19 @@ void *nextTreeData(TreeNode *root)
 // Releases all memory resources (including data copies).
 void clearTree(TreeNode *root)
 {
-
+    if (root == NULL) {
+        clearTree(root->left);
+        clearTree(root->right);
+        free(root->data);
+        free(root);
+    }
 }
 
 // Returns the number of entries in the tree given by root.
 unsigned int treeSize(const TreeNode *root)
 {
-
+    if (root == NULL) {
+        return 0;
+    }
+    return 1 + treeSize(root->left) + treeSize(root->right);
 }