C Program for binary search tree deletion without recursion

By | April 17, 2017

Binary search tree deletion without recursion


Write a C Program for binary search tree deletion without recursion. Here’s simple Program for binary search tree deletion without recursion in C Programming Language.


What is Tree ?


In linear data structure, data is organized in sequential order and in non-linear data structure, data is organized in random order. Tree is a very popular data structure used in wide range of applications.

A tree data structure can be defined as follows…

  • Tree is a non-linear data structure which organizes data in hierarchical structure and this is a recursive definition.

A tree data structure can also be defined as follows…

  • Tree data structure is a collection of data (Node) which is organized in hierarchical structure and this is a recursive definition.

Every individual element is called as Node. Node in a tree data structure, stores the actual data of that particular element and link to next element in hierarchical structure.


Below is the source code for C Program for binary search tree deletion without recursion which is successfully compiled and run on Windows System to produce desired output as shown below :


SOURCE CODE : :


/*  C Program for binary search tree deletion without recursion  */

#include<stdio.h>
#include<stdlib.h>
#define MAX 50

struct node
{
	struct node *lchild;
	int info;
	struct node *rchild;
};

struct node *insert_nrec(struct node *root, int ikey );
struct node *del_nrec(struct node *root, int dkey);
struct node *case_c(struct node *root, struct node *par,struct node *ptr);
struct node *case_b(struct node *root,struct node *par,struct node *ptr);
struct node *case_a(struct node *root, struct node *par,struct node *ptr );
void display(struct node *ptr,int level);



int main( )
{
	struct node *root=NULL, *ptr;
	int choice,k;

	while(1)
	{
		printf("\n");
		printf("1.Insert\n");
		printf("2.Delete\n");
		printf("3.Display\n");
		printf("4.Quit\n");
		printf("\nEnter your choice : ");
		scanf("%d",&choice);

		switch(choice)
		{

		case 1:
			printf("Enter the key to be inserted : ");
			scanf("%d",&k);
			root = insert_nrec(root, k);
			break;

		case 2:
			printf("Enter the key to be deleted : ");
			scanf("%d",&k);
			root = del_nrec(root, k);
			break;

        case 3:
			printf("\n");
			display(root,0);
			printf("\n");
			break;

		case 4:
			exit(1);
			
		default:
			printf("Wrong choice\n");
			
		}/*End of switch*/
	}/*End of while */
	
	return 0;
	
}/*End of main( )*/


struct node *insert_nrec(struct node *root, int ikey)
{
	struct node *tmp,*par,*ptr;

	ptr = root;
	par = NULL;

	while( ptr!=NULL)
	{
		par = ptr;
		if(ikey < ptr->info)
			ptr = ptr->lchild;
		else if( ikey > ptr->info )
			ptr = ptr->rchild;
		else
		{
			printf("Duplicate key");
			return root;
		}
	}

	tmp=(struct node *)malloc(sizeof(struct node));
	tmp->info=ikey;
	tmp->lchild=NULL;
	tmp->rchild=NULL;

	if(par==NULL)
		root=tmp;
	else if( ikey < par->info )
		par->lchild=tmp;
	else
		par->rchild=tmp;

	return root;
}/*End of insert_nrec( )*/


struct node *del_nrec(struct node *root, int dkey)
{
	struct node *par,*ptr;

	ptr = root;
	par = NULL;
	while(ptr!=NULL)
	{
		if( dkey == ptr->info)
			break;
		par = ptr;
		if(dkey < ptr->info)
			ptr = ptr->lchild;
		else
			ptr = ptr->rchild;
	}

	if(ptr==NULL)
		printf("dkey not present in tree\n");
	else if(ptr->lchild!=NULL && ptr->rchild!=NULL)/*2 children*/
		root = case_c(root,par,ptr);
	else if(ptr->lchild!=NULL )/*only left child*/
        root = case_b(root, par,ptr);
	else if(ptr->rchild!=NULL)/*only right child*/
        root = case_b(root, par,ptr);
	else /*no child*/
		root = case_a(root,par,ptr);

	return root;
}/*End of del_nrec( )*/

struct node *case_a(struct node *root, struct node *par,struct node *ptr )
{
	if(par==NULL) /*root node to be deleted*/
		root=NULL;
	else if(ptr==par->lchild)
		par->lchild=NULL;
	else
		par->rchild=NULL;
	free(ptr);
	return root;
}/*End of case_a( )*/

struct node *case_b(struct node *root,struct node *par,struct node *ptr)
{
	struct node *child;

	/*Initialize child*/
	if(ptr->lchild!=NULL) /*node to be deleted has left child */
		child=ptr->lchild;
	else                /*node to be deleted has right child */
		child=ptr->rchild;

	if(par==NULL )   /*node to be deleted is root node*/
		root=child;
	else if( ptr==par->lchild)   /*node is left child of its parent*/
		par->lchild=child;
	else                  /*node is right child of its parent*/
		par->rchild=child;
	free(ptr);
	return root;
}/*End of case_b( )*/

struct node *case_c(struct node *root, struct node *par,struct node *ptr)
{
	struct node *succ,*parsucc;

	/*Find inorder successor and its parent*/
	parsucc = ptr;
	succ = ptr->rchild;
	while(succ->lchild!=NULL)
	{
		parsucc = succ;
		succ = succ->lchild;
	}

	ptr->info = succ->info;

	if(succ->lchild==NULL && succ->rchild==NULL)
		root = case_a(root, parsucc,succ);
	else
		root = case_b(root, parsucc,succ);
	return root;
}/*End of case_c( )*/


void display(struct node *ptr,int level)
{
	int i;
	if(ptr == NULL )/*Base Case*/
		return;
	else
    {
		display(ptr->rchild, level+1);
		printf("\n");
		for (i=0; i<level; i++)
			printf("    ");
		printf("%d", ptr->info);
		display(ptr->lchild, level+1);
	}
}/*End of display()*/

OUTPUT : :


/*  C Program for binary search tree deletion without recursion  */

1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 5                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 3                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 4                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
              
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 2                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 7                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 6                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 1                                                                                                                                                           
Enter the key to be inserted : 8                                                                                                                                                
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3                                                                                                                                                           
                                                                                                                                                                                
                                                                                                                                                                                
        8                                                                                                                                                                       
    7                                                                                                                                                                           
        6                                                                                                                                                                       
5                                                                                                                                                                               
        4                                                                                                                                                                       
    3                                                                                                                                                                           
        2                                                                                                                                                                       
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 2                                                                                                                                                           
Enter the key to be deleted : 7                                                                                                                                                 
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3  

   8                                                                                                                                                                           
        6                                                                                                                                                                       
5                                                                                                                                                                               
        4                                                                                                                                                                       
    3                                                                                                                                                                           
        2                                                                                                                                                                       
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 2                                                                                                                                                           
Enter the key to be deleted : 3                                                                                                                                                 
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3                                                                                                                                                           
                                                                                                                                                                                
                                                                                                                                                                                
    8                                                                                                                                                                           
        6                                                                                                                                                                       
5                                                                                                                                                                               
    4                                                                                                                                                                           
        2  

1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 2                                                                                                                                                           
Enter the key to be deleted : 6                                                                                                                                                 
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3                                                                                                                                                           
                                                                                                                                                                                
                                                                                                                                                                                
    8                                                                                                                                                                           
5                                                                                                                                                                               
    4                                                                                                                                                                           
        2                                                                                                                                                                       
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit       

Enter your choice : 2                                                                                                                                                           
Enter the key to be deleted : 5                                                                                                                                                 
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3                                                                                                                                                           
                                                                                                                                                                                
                                                                                                                                                                                
8                                                                                                                                                                               
    4                                                                                                                                                                           
        2                                                                                                                                                                       
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 2                                                                                                                                                           
Enter the key to be deleted : 8                                                                                                                                                 
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 3 

                                                                                                                                                                                
4                                                                                                                                                                               
    2                                                                                                                                                                           
                                                                                                                                                                                
1.Insert                                                                                                                                                                        
2.Delete                                                                                                                                                                        
3.Display                                                                                                                                                                       
4.Quit                                                                                                                                                                          
                                                                                                                                                                                
Enter your choice : 4

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