From e63c806f25ee217b2628ff172a92c4eb9de683d2 Mon Sep 17 00:00:00 2001 From: Amit Date: Thu, 11 Jun 2020 19:35:59 +0530 Subject: [PATCH] updated documentation and format --- .../binary_trees/Threaded_Binary_Tree.c | 462 +++++++++--------- 1 file changed, 222 insertions(+), 240 deletions(-) diff --git a/data_structures/binary_trees/Threaded_Binary_Tree.c b/data_structures/binary_trees/Threaded_Binary_Tree.c index 2804c36b..1be03183 100644 --- a/data_structures/binary_trees/Threaded_Binary_Tree.c +++ b/data_structures/binary_trees/Threaded_Binary_Tree.c @@ -1,260 +1,242 @@ -#include -#include +/** + * @file + * \brief Threaded Binary Tree is a binary tree variant in which all left child + * pointers that are NULL (in Linked list representation) point to its + * in-order predecessor, and all right child pointers that are NULL + * (in Linked list representation) point to its in-order successor. + * This file is a simple implementation of a Threaded Binary Tree + * with the following functionalities: + * - Insertion + * - Search + * - Deletion + * - Listing of node keys inorder,preorder,postorder + * \author [Amitha Nayak](https://github.com/amitnayakblr) + */ -/*Threaded Binary Tree is a binary tree variant in which all left child -pointers that are NULL (in Linked list representation) point to its -in-order predecessor, and all right child pointers that are NULL -(in Linked list representation) point to its in-order successor. +#include +#include -This file is a simple implementation of a Threaded Binary Tree -with the following functionalities: - - Insertion - - Search - - Deletion - - Listing of node keys inorder,preorder, postorder -*/ +/** + * Node, the basic data structure of the tree + **/ +typedef struct Node { + int data; /**< stores the number */ + struct Node *llink; /**< link to left child */ + struct Node *rlink; /**< link to right child */ +} node; -// Node, the basic data structure in the tree -typedef struct Node -{ - int data; - struct Node *llink; - struct Node *rlink; -}node; - -node* create_node(int data) -{ - node *ptr=(node*) malloc(sizeof(node)); - ptr->rlink=ptr->llink=NULL; - ptr->data=data; - return ptr; +/** + * creates a new node + * param[in] data value to be inserted + * \returns a pointer to the new node + **/ +node *create_node(int data) { + node *ptr = (node *)malloc(sizeof(node)); + ptr->rlink = ptr->llink = NULL; + ptr->data = data; + return ptr; } -void insert_BT(node **root,int data) -{ - node *new_node=create_node(data); - node *temp; //to be deleted - node *prev; //keeps track of the parent of the element deleted - if(*root==NULL) - { - *root=new_node; - } - else - { - temp=*root; - prev=NULL; - while(temp!=NULL) - { - if(new_node->data>temp->data) - { - prev=temp; - temp=temp->rlink; - } - else if(new_node->datadata) - { - prev=temp; - temp=temp->llink; - } - else - { - return; - } - } +/** + * inserts a node into the tree + * param[in,out] root pointer to node pointer to the topmost node of the tree + * param[in] data value to be inserted into the tree + */ +void insert_BT(node **root, int data) { + node *new_node = create_node(data); + node *temp; // to be deleted + node *prev; // keeps track of the parent of the element deleted + if (*root == NULL) { + *root = new_node; + } else { + temp = *root; + prev = NULL; + while (temp != NULL) { + if (new_node->data > temp->data) { + prev = temp; + temp = temp->rlink; + } else if (new_node->data < temp->data) { + prev = temp; + temp = temp->llink; + } else { + return; + } + } - if(new_node->data>prev->data) - { - prev->rlink=new_node; - } - else - { - prev->llink=new_node; - } - } + if (new_node->data > prev->data) { + prev->rlink = new_node; + } else { + prev->llink = new_node; + } + } } -// returns "Element found" if the search element is present else returns, "Element not found" -void search(node *root, int ele) -{ - node *temp=root; - while(temp!=NULL) - { - if(temp->data==ele) - { - break; - } - else if(ele>temp->data) - { - temp=temp->rlink; - } - else - { - temp=temp->llink; - } - } +/** + * searches for the element + * \param[in] root node pointer to the topmost node of the tree + * \param[in] ele value searched for + */ +void search(node *root, int ele) { + node *temp = root; + while (temp != NULL) { + if (temp->data == ele) { + break; + } else if (ele > temp->data) { + temp = temp->rlink; + } else { + temp = temp->llink; + } + } - if(temp==NULL) - { - printf("%s\n","Element not found." ); - } - else printf("%s\n","Element found." ); + if (temp == NULL) { + printf("%s\n", "Element not found."); + } else + printf("%s\n", "Element found."); } -void inorder_display(node *curr) -{ - if(curr!=NULL) - { - inorder_display(curr->llink); - printf("%d\t",curr->data ); - inorder_display(curr->rlink); - } - +/* + * performs inorder traversal + * param[in] curr node pointer to the topmost node of the tree + */ +void inorder_display(node *curr) { + if (curr != NULL) { + inorder_display(curr->llink); + printf("%d\t", curr->data); + inorder_display(curr->rlink); + } } -void postorder_BT(node *curr) -{ - if(curr!=NULL) - { - postorder_BT(curr->llink); - postorder_BT(curr->rlink); - printf("%d\t",curr->data); - } - +/* + * performs postorder traversal + * param[in] curr node pointer to the topmost node of the tree + */ +void postorder_BT(node *curr) { + if (curr != NULL) { + postorder_BT(curr->llink); + postorder_BT(curr->rlink); + printf("%d\t", curr->data); + } } -void preorder_BT(node *curr) -{ - if(curr!=NULL) - { - printf("%d\t",curr->data); - preorder_BT(curr->llink); - preorder_BT(curr->rlink); - } +/* + * performs preorder traversal + * param[in] curr node pointer to the topmost node of the tree + */ +void preorder_BT(node *curr) { + if (curr != NULL) { + printf("%d\t", curr->data); + preorder_BT(curr->llink); + preorder_BT(curr->rlink); + } } -// deletes the node if present, else it takes no action. -void delete_BT(node **root,int ele) -{ - node* temp; - node *prev; - if(*root==NULL) return; - else - { - temp=*root; - prev=NULL; - // search - while(temp!=NULL) - { - if(temp->data==ele) - { - break; - } - else if(ele>temp->data) - { - prev=temp; - temp=temp->rlink; - } - else - { - prev=temp; - temp=temp->llink; - } - } - } +/* + * deletion of a node from the tree + * if the node isn't present in the tree, it takes no action. + * param[in,out] root pointer to node pointer to the topmost node of the tree + * param[in] ele value to be deleted from the tree + */ +void delete_BT(node **root, int ele) { + node *temp; + node *prev; + if (*root == NULL) + return; + else { + temp = *root; + prev = NULL; + // search + while (temp != NULL) { + if (temp->data == ele) { + break; + } else if (ele > temp->data) { + prev = temp; + temp = temp->rlink; + } else { + prev = temp; + temp = temp->llink; + } + } + } - if(temp==NULL) - return; - else - { - node *replacement; //deleted node's replacement - node *t; - if(temp->llink==NULL && temp->rlink==NULL) - { - replacement=NULL; - } - else if(temp->llink==NULL && temp->rlink!=NULL) - { - replacement=temp->rlink; - } - else if(temp->llink!=NULL && temp->rlink==NULL) - { - replacement=temp->llink; - } - else - { - replacement=temp->rlink; //replaced with inorder successor - t=replacement; - while(t->llink!=NULL) - { - t=t->llink; - } - t->llink=temp->llink; //leftmost node of the replacement is linked to the left child of the deleted node - } + if (temp == NULL) + return; + else { + node *replacement; // deleted node's replacement + node *t; + if (temp->llink == NULL && temp->rlink == NULL) { + replacement = NULL; + } else if (temp->llink == NULL && temp->rlink != NULL) { + replacement = temp->rlink; + } else if (temp->llink != NULL && temp->rlink == NULL) { + replacement = temp->llink; + } else { + replacement = temp->rlink; // replaced with inorder successor + t = replacement; + while (t->llink != NULL) { + t = t->llink; + } + t->llink = temp->llink; // leftmost node of the replacement is linked to + // the left child of the deleted node + } - if(temp==*root) - { - free(*root); - *root=replacement; - } - else if(prev->llink==temp) - { - free(prev->llink); - prev->llink=replacement; - } - else if(prev->rlink==temp) - { - free(prev->rlink); - prev->rlink=replacement; - } - } - } - - -void main() -{ - printf("BINARY TREE: \n"); - node *root=NULL; - int choice,n; - do - { - printf("%s\n","1. Insert into BT" ); - printf("%s\n","2. Print BT - inorder" ); - printf("%s\n","3. Print BT - preorder" ); - printf("%s\n","4. print BT - postorder" ); - printf("%s\n","5. delete from BT" ); - printf("%s\n","6. search in BT" ); - scanf("%d",&choice); - - - switch(choice) - { - case 1: - printf("%s\n","Enter a no:" ); - scanf("%d",&n); - insert_BT(&root,n); - break; - case 2: - inorder_display(root); - printf("\n"); - break; - case 3: - preorder_BT(root); - printf("\n"); - break; - case 4: - postorder_BT(root); - printf("\n"); - break; - case 5: - printf("%s\n","Enter a no:" ); - scanf("%d",&n); - delete_BT(&root,n); - break; - case 6: - printf("%s\n","Enter a no:" ); - scanf("%d",&n); - search(root,n); - break; - } - - }while(choice!=0); + if (temp == *root) { + free(*root); + *root = replacement; + } else if (prev->llink == temp) { + free(prev->llink); + prev->llink = replacement; + } else if (prev->rlink == temp) { + free(prev->rlink); + prev->rlink = replacement; + } + } +} + +/* + * main function + */ +void main() { + printf("BINARY THREADED TREE: \n"); + node *root = NULL; + int choice, n; + do { + printf("%s\n", "1. Insert into BT"); + printf("%s\n", "2. Print BT - inorder"); + printf("%s\n", "3. Print BT - preorder"); + printf("%s\n", "4. print BT - postorder"); + printf("%s\n", "5. delete from BT"); + printf("%s\n", "6. search in BT"); + printf("%s\n", "Type 0 to exit"); + scanf("%d", &choice); + + switch (choice) { + case 1: + printf("%s\n", "Enter a no:"); + scanf("%d", &n); + insert_BT(&root, n); + break; + case 2: + inorder_display(root); + printf("\n"); + break; + case 3: + preorder_BT(root); + printf("\n"); + break; + case 4: + postorder_BT(root); + printf("\n"); + break; + case 5: + printf("%s\n", "Enter a no:"); + scanf("%d", &n); + delete_BT(&root, n); + break; + case 6: + printf("%s\n", "Enter a no:"); + scanf("%d", &n); + search(root, n); + break; + } + } while (choice != 0); }