feat: update structure

cs2106/labs/lab1/part3/phonebook.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include "phonebook.h"
+#include "bintree.h"
+
+static TTreeNode *_root = NULL;
+
+char *findPerson(char *name)
+{
+    TTreeNode *node, *prev;
+    findNode(name, _root, &node, &prev);
+
+    if (node != NULL)
+        return node->phoneNum;
+    else
+        return NULL;
+}
+
+void print_phonebook()
+{
+    print_inorder(_root);
+}
+
+void addPerson(char *name, char *phoneNum)
+{
+    if (findPerson(name) == NULL)
+    {
+        TTreeNode *node = makeNewNode(name, phoneNum);
+        addNode(&_root, node);
+    }
+    else
+        printf("%s is already in phonebook.\n", name);
+}
+
+void delPerson(char *name)
+{
+    TTreeNode *node, *prevnode;
+    findNode(name, _root, &node, &prevnode);
+    if (node == NULL)
+    {
+        printf("Unable to find %s\n", name);
+        return;
+    }
+
+    delNode(node, prevnode);
+}
+
+void delPhonebook()
+{
+    delTree(_root);
+    _root = NULL;
+}