How to know avl node status in C? - c

Question

This exercise is not really new to me, but it still is quite advance for me. Being a student, I would like to kindly ask for your help regarding this matter.
I need to understand, not just know, how AVL node deletion works. I've been given this C code that I have to complete to demonstrate how AVL insertion and deletion happens. I've done the basics. It's just the balancing and the rotation that got me dizzy.
Here's the main C file:
#include<stdio.h>
#include<stdlib.h>
#include "avl.h"
#define N 10
#define BALANCED 0
#define LEFT_LEANING 1
#define RIGHT_LEANING 2
int main(){
AVL *root=NULL;
int choice=0,x;
while((choice=menu())!=3){
printf("Value: ");
scanf("%i",&x);
switch(choice){
case 1: insert_value(&root,x);
view(root,2);
break;
case 2: delete_value(&root,x);
view(root,2);
}
}
}
here's the avl header file:
#define N 10
#define BALANCED 0
#define LEFT_LEANING 1
#define RIGHT_LEANING 2
//structure for an avl_node
typedef struct node_tag{
int x, height;
struct node_tag *parent;
struct node_tag *left;
struct node_tag *right;
}avl_node;
//print menu and get user choice
int menu(){
int choice;
printf("\n MENU ");
printf("\n[1] - Insert");
printf("\n[2] - Delete");
printf("\n[3] - Exit");
printf("\nYour choice: ");
scanf("%i",&choice);
return choice;
}
//find maximum of 2 numbers
int max(int a,int b){
return(a>b?a:b);
}
//finds the minimum value of the BST
avl_node* minimum(avl_node *rootptr){
if(rootptr!=NULL){
while(rootptr->left!=NULL) rootptr=rootptr->left;
}
return (rootptr);
}
//update height of a given node
void updateheight(avl_node *temp){
if(temp!=NULL)
temp->height = max(temp->left==NULL?-1:temp->left->height,temp->right==NULL?-1:temp->right->height)+1;
}
//left rotate the subtree
void left_rotate(avl_node **rootptr){
}
//right rotate the subtree
void right_rotate(avl_node **rootptr){
}
//determine rotation of node/s
void insert_fixup(avl_node **rootptr, avl_node *temp){
}
//insert value and create node
void insert_value(avl_node **rootptr, int x){
avl_node *temp;
temp = (avl_node *)malloc(sizeof(avl_node));
temp->x = x;
temp->height = 0;
temp->parent = temp->left = temp->right = NULL;
insert_node(rootptr,temp);
insert_fixup(rootptr,temp);
}
void view(avl_node *root, int tabs){
int i;
if(root != NULL){
view(root->right,tabs + 1);
for(i=0;i<tabs;i++) printf("\t");
printf("%2i\n",root->x);
view(root->left,tabs+1);
}
}//view the AVL
void swap(int *a, int *b){
int temp;
temp = *a; *a = *b; *b = temp;
}//swap values
//look for the successor of a node
avl_node* successor(avl_node *rootptr){
if(rootptr==NULL) return (rootptr);
else if(rootptr->right!=NULL) return (minimum(rootptr->right));
while(rootptr->parent!=NULL){
if(rootptr==rootptr->parent->right) rootptr=rootptr->parent;
else break;
}
return (rootptr->parent);
}
//function for searching the location of the node
avl_node* search(avl_node *root,int x){
if(root==NULL || root->x==x) return root;
else{
if(root->x>x) return(search(root->left,x));
else return(search(root->right,x));
}
}
//function for searching the value of the node
int search_node(avl_node *root, int x){
if(root==NULL) return 0;
if(root->x==x) return 1;
else{
if(root->x>x) return(search_node(root->left,x));
else return(search_node(root->right,x));
}
}
//function for deleting a node
void delete_value(avl_node** root,int x){
}

Answer 1

To understand, You should go through the Wiki Page and also try to understand pseudo code to understand node insertion and deletion in AVL tree. Also you can go through Presentation PPT to understand AVL tree. And to find status of your node from tree you can use search() function.