feat: update structure

cs2106/labs/lab1/part3/bintree.c

@@ -0,0 +1,210 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "bintree.h"
+
+/* ------------------------- DO NOT IMPLEMENT THESE ----------------------
+
+These are provided "free" to you, and you do not need to implement them,
+though you MAY  need to understand what they do. Some give you hints
+on how to work with pointers to pointers. You MAY find some of these
+functions useful.
+
+  ------------------------------------------------------------------------- */
+
+// Searches for the node containing "name" in the tree whose root is at "root",
+// returning both the node ifself in "node", and its parent in "prevnode"
+// (useful for deleting node). Both "node" and "prevnode" are set to NULL
+// if name is not found in the tree.
+
+void findNode(char *name, TTreeNode *root, TTreeNode **node, TTreeNode **prevnode)
+{
+
+    TTreeNode *trav = root;
+    TTreeNode *prev = NULL;
+
+    while (trav != NULL)
+    {
+        int cmp = strcmp(trav->name, name);
+
+        if (cmp == 0)
+        {
+            *node = trav;
+            *prevnode = prev;
+            return;
+        }
+
+        prev = trav;
+        if (cmp < 0)
+            trav = trav->right;
+        else
+            trav = trav->left;
+    }
+
+    *node = NULL;
+    *prevnode = NULL;
+}
+
+// Searches for the node with the smallest value ("smallest node") in the tree originating at "node".
+// Returns the smallest node and its parent in "smallest_node" and "parent"
+// respectively.
+void findSmallest(TTreeNode *node, TTreeNode **smallest_node, TTreeNode **parent)
+{
+    TTreeNode *trav = node;
+    TTreeNode *prev = NULL;
+
+    if (trav == NULL)
+        return;
+
+    while (trav->left != NULL)
+    {
+        prev = trav;
+        trav = trav->left;
+    }
+
+    *smallest_node = trav;
+    *parent = prev;
+}
+
+// Delete a node at "node" with parent node "prevnode"
+void delNode(TTreeNode *node, TTreeNode *prevnode)
+{
+    // This is a leaf node
+    if (node->left == NULL && node->right == NULL)
+    {
+        // See whether node is on parent's left or right, and NULL the
+        // corresponding pointer
+
+        int cmp = strcmp(prevnode->name, node->name);
+
+        // Previous node is smaller than this one. This
+        // node is on the right
+        if (cmp < 0)
+            prevnode->right = NULL;
+        else
+            prevnode->left = NULL;
+
+        freenode(node);
+
+        return;
+    }
+
+    // This has a child on the left only
+    if (node->right == NULL)
+    {
+        // Copy the right child over
+        node = node->left;
+        freenode(node->left);
+        return;
+    }
+
+    // This has a child on the right only
+    if (node->left == NULL)
+    {
+        node = node->right;
+        freenode(node->right);
+        return;
+    }
+
+    // This has children on both nodes
+    TTreeNode *smallest, *smallest_parent;
+    findSmallest(node->right, &smallest, &smallest_parent);
+    node = smallest;
+    smallest_parent->left = NULL;
+    freenode(smallest);
+}
+
+/* ---------------------------- IMPLEMENT THESE --------------------------- */
+
+// Create a new node with name set to "name" and
+// phoneNum set to "phoneNum".
+void delTree(TTreeNode *root)
+{
+    // Implement deleting the entire tree, whose
+    // root is at "root".
+    if (root == NULL)
+        return;
+    if (root->left != NULL)
+        delTree(root->left);
+    if (root->right != NULL)
+        delTree(root->right);
+    freenode(root);
+}
+
+TTreeNode *makeNewNode(char *name, char *phoneNum)
+{
+    TTreeNode *node = malloc(sizeof(TTreeNode));
+    node->name = malloc(strlen(name) + 1);
+    strcpy(node->name, name);
+    strcpy(node->phoneNum, phoneNum);
+    node->left = NULL;
+    node->right = NULL;
+    return node;
+    // Implement makeNewNode to create a new
+    // TTreeNode containing name and phoneNum
+}
+
+// Add a new node to the tree.
+// Note that "root" is a POINTER to the tree's root,
+// not the root itself.
+
+void addNode(TTreeNode **root, TTreeNode *node)
+{
+    if (*root == NULL)
+    {
+        *root = node;
+    }
+
+    TTreeNode **trav = root;
+
+    while (1)
+    {
+
+        int cmp = strcmp((*trav)->name, node->name);
+        if (cmp == 0)
+            return;
+        if (cmp > 0)
+        {
+            if ((*trav)->left == NULL)
+                (*trav)->left = node;
+            else
+            {
+                trav = &((*trav)->left);
+                continue;
+            }
+        }
+        else if (cmp < 0)
+        {
+            if ((*trav)->right == NULL)
+                (*trav)->right = node;
+            else
+            {
+                trav = &((*trav)->right);
+                continue;
+            }
+        }
+    }
+
+    // Add a new node to the tree, where root is
+    // the POINTER to the tree's root.
+}
+
+void freenode(TTreeNode *node)
+{
+    free(node->name);
+    free(node);
+    // Frees the memory used by node.
+}
+
+void print_inorder(TTreeNode *node)
+{
+    // Implement in-order printing of the tree
+    // Recursion is probably best here.
+
+    if (node == NULL)
+        return;
+    if (node->left != NULL)
+        print_inorder(node->left);
+    printf("Name is %s  Number is %s\n", node->name, node->phoneNum);
+    if (node->right != NULL)
+        print_inorder(node->right);
+}