Make a habit to use Iterative Macro for iterating Data Structure

Iterative_macros/tree.c

@@ -0,0 +1,153 @@
+/*
+ * =====================================================================================
+ *
+ *       Filename:  tree.c
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 09:51:42 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+#include "tree.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+
+tree_t*
+init_tree(void)
+{
+    tree_t *tree = calloc(1,sizeof(tree_t));
+    if(!tree)
+        return NULL;
+    tree->root = NULL;
+    return tree;
+}
+
+tree_node_t* init_tree_node(int n)
+{
+    tree_node_t *node = calloc(1, sizeof(tree_node_t));
+    if(!node)   return NULL;
+    node->data = n;
+    return node;
+}
+
+int
+add_tree_node_by_value(tree_t *tree, int n)
+{
+    tree_node_t *root = NULL, *parent = NULL;;
+    if(!tree) return -1;
+    tree_node_t *node = init_tree_node(n);
+    if(!tree->root){
+        tree->root = node;
+        return 0;
+    }
+
+    root = tree->root;
+
+    while(root){
+        parent = root;
+        root = (n <= root->data) ? root->left : root->right;
+    } // while ends
+
+    if(n <= parent->data)
+        parent->left = node;
+    else
+        parent->right = node;
+
+    node->parent = parent;
+    return 0;
+}
+
+tree_node_t *
+get_left_most(tree_node_t *node){
+
+    if(!node->left)
+        return NULL;
+
+    while(node->left){
+        node = node->left;
+    }
+    return node;
+}
+
+tree_node_t *
+get_next_inorder_succ(tree_node_t *node){
+
+    /* case 1 : Handling root*/
+    if(!node->parent){
+        if(node->right){
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+        }
+        return NULL;
+    }
+
+    /*case 2 : if node is a left child of its parent*/
+    if(node == node->parent->left){
+        if(!node->right)
+            return node->parent;
+        else
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+    }
+
+    /*case 3 : if node is a right child of its parent*/
+    if(node == node->parent->right){
+        if(node->right){
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+        }
+    }
+
+    /* case 4 : Inorder successor of node is a ancestor whose
+     * left children is also an ancestor*/
+
+    tree_node_t *gp = node->parent->parent;
+    tree_node_t *parent = node->parent;
+
+    while(gp && gp->left != parent){
+
+        parent = gp;
+        gp = gp->parent;
+    }
+
+    return gp;
+}
+
+int
+main(int argc, char **argv){
+
+    tree_t *tree = init_tree();
+
+    add_tree_node_by_value(tree,  100);
+    add_tree_node_by_value(tree,  50);
+    add_tree_node_by_value(tree,  10);
+    add_tree_node_by_value(tree,  90);
+    add_tree_node_by_value(tree,  95);
+    add_tree_node_by_value(tree,  99);
+    
+    tree_node_t *treenodeptr = NULL;
+
+    ITERATE_BST_BEGIN(tree, treenodeptr){
+    
+        printf("%u ", treenodeptr->data);
+
+    } ITERATE_BST_END;
+    printf("\n");
+    
+    return 0;
+}