Deletion in Circular linked list: Beginning and End

May 10, 2025February 4, 2021 by quescol

C Program to Delete a node in circular linked list at Beginning

#include<stdio.h> 
#include<conio.h>
#include<stdlib.h>
struct node{
    int data;
    struct node *next;
    };
struct node *head=NULL;
struct node* createNode(){
    struct node *newNode = (struct node *)malloc(sizeof(struct node));
    return (newNode);
    }
 
void insertNode(){
	struct node *temp,*ptr;
	temp=createNode();
	printf("enter the data you want to insert:");
	scanf("%d",&temp->data);
	temp->next=NULL;
	if(head==NULL){
		head=temp;
		head->next=head;
	}
	else{
		ptr=head;
		while(ptr->next!=head){
			ptr=ptr->next;
		}
	       ptr->next=temp;
	       temp->next=head;
	     }
    }
 
void deleteNodeAtBegin(){
    if(head==NULL){
		printf("list is empty");
	}
	else{
		struct node* temp=head;
        struct node* ptr=head;
        while(ptr->next!=head){
		    ptr =ptr->next;
	    }
        head=head->next;
        ptr ->next=head;
        printf("\n deleted node with value %d",temp->data);
		free(temp);
	    }
    }
void viewList(){
    struct node* temp=head;
	if(temp==NULL){
		printf("list is empty");
	}
	else{
	    printf("Values of Cicular list \n");
		while(temp->next!=head)
		{
			printf("%d\t",temp->data);
			temp=temp->next;
		}
		printf("%d \t",temp->data);
	}
}
 
int menu(){
    int choice;
    printf("\n 1.Add value to the list");
    printf("\n 2.Delete node at Begining");
    printf("\n 3.Travesre/View List");
    printf("\n 4.Exit");
    printf("\n Please enter your choice: \t");
    scanf("%d",&choice);
    return(choice);
}
void main(){
    printf("Delete a node in circular linked list at Beginning");
    while(1){
        switch(menu()){
            case 1:
                insertNode();
                break;
            case 2:
                deleteNodeAtBegin();
                break;
            case 3:
                viewList();
                break;
            case 4:
                exit(0);
            default:
                printf("invalid choice");
        }
    }
    getch();
}

Output:

Delete a node in circular linked list at Beginning
 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      1
enter the data you want to insert:4

 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      1
enter the data you want to insert:3

 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      1
enter the data you want to insert:3

 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      1
enter the data you want to insert:7

 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      3
Values of Cicular list 
4       3       3       7 
 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      2

 deleted node with value 4
 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      3
Values of Cicular list 
3       3       7 
 1.Add value to the list
 2.Delete node at Begining
 3.Travesre/View List
 4.Exit
 Please enter your choice:      4

C Program to Delete a node in Circular linked list at End

#include<stdio.h> 
#include<conio.h>
#include<stdlib.h>
struct node{
    int data;
    struct node *next;
    };
struct node *head=NULL;
struct node* createNode(){
    struct node *newNode = (struct node *)malloc(sizeof(struct node));
     
return (newNode);
    }
 
void insertNode(){
	struct node *temp,*ptr;
	temp=createNode();
	printf("enter the data you want to insert:");
	scanf("%d",&temp->data);
	temp->next=NULL;
	if(head==NULL){
		head=temp;
		head->next=head;
	}
	else{
		ptr=head;
		while(ptr->next!=head){
			ptr=ptr->next;
		}
	       ptr->next=temp;
	       temp->next=head;
	     }
    }
 
void deleteNodeAtEnd(){
	struct node *temp,*secondLast;
	if(head==NULL){
		printf("list is empty");
	}
	else{
		temp=head;
		secondLast=head;
		while(temp->next!=head){
			secondLast=temp;
			temp=temp->next;
		}
		if(temp==head){
			head=NULL;
		}
		else{
			secondLast->next=head;
		}
		free(temp);
	}
 }
void viewList(){
    struct node* temp=head;
	if(temp==NULL){
		printf("list is empty");
	}
	else{
	    printf("Values of Cicular list \n");
		while(temp->next!=head)
		{
			printf("%d\t",temp->data);
			temp=temp->next;
		}
		printf("%d \t",temp->data);
	}
}
 
int menu(){
    int choice;
    printf("\n 1.Add value to the list");
    printf("\n 2.Delete node at End");
    printf("\n 3.Travesre/View List");
    printf("\n 4. exit");
    printf("\n Please enter your choice: \t");
    scanf("%d",&choice);
    return(choice);
}
void main(){
    printf("Delete a node in circular linked list at End");
    while(1){
        switch(menu()){
            case 1:
                insertNode();
                break;
            case 2:
                deleteNodeAtEnd();
                break;
            case 3:
                viewList();
                break;
            case 4:
                exit(0);
            default:
                printf("invalid choice");
        }
    }
        getch();
    }

Output:

Delete a node in circular linked list at End
 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      1
enter the data you want to insert:3

 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      1
enter the data you want to insert:6

 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      1
enter the data you want to insert:3

 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      1
enter the data you want to insert:7

 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      3
Values of Cicular list 
3       6       3       7 
 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      2

 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      3 
Values of Cicular list 
3       6       3 
 1.Add value to the list
 2.Delete node at End
 3.Travesre/View List
 4. exit
 Please enter your choice:      4

C Program to Delete a node in circular linked list at Given Location

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

struct node {
    int data;
    struct node *next;
};

struct node *head = NULL;

struct node* createNode() {
    struct node *newNode = (struct node *)malloc(sizeof(struct node));
    return newNode;
}

void insertNode() {
    struct node *temp, *ptr;
    temp = createNode();
    printf("Enter the data you want to insert: ");
    scanf("%d", &temp->data);
    temp->next = NULL;

    if (head == NULL) {
        head = temp;
        head->next = head;
    } else {
        ptr = head;
        while (ptr->next != head) {
            ptr = ptr->next;
        }
        ptr->next = temp;
        temp->next = head;
    }
}

void deleteNodeAtPosition(int position) {
    if (head == NULL) {
        printf("List is empty.\n");
        return;
    }

    struct node *temp = head, *prev = NULL;
    int count = 1;

    // Case 1: Delete head node
    if (position == 1) {
        int deletedData = head->data;
        if (head->next == head) {
            free(head);
            head = NULL;
        } else {
            struct node *last = head;
            while (last->next != head)
                last = last->next;
            last->next = head->next;
            temp = head;
            head = head->next;
            free(temp);
        }
        printf("Deleted node value: %d\n", deletedData);
        return;
    }

    // Traverse to the node at (position - 1)
    while (count < position && temp->next != head) {
        prev = temp;
        temp = temp->next;
        count++;
    }

    if (count != position) {
        printf("Invalid position.\n");
        return;
    }

    int deletedData = temp->data;
    prev->next = temp->next;
    free(temp);
    printf("Deleted node value: %d\n", deletedData);
}


void viewList() {
    struct node* temp = head;
    if (temp == NULL) {
        printf("List is empty.\n");
    } else {
        printf("Values of Circular list:\n");
        while (temp->next != head) {
            printf("%d\t", temp->data);
            temp = temp->next;
        }
        printf("%d\t", temp->data);
    }
}

int menu() {
    int choice;
    printf("\n\n***** MENU *****");
    printf("\n 1. Add value to the list");
    printf("\n 2. Delete node from given position");
    printf("\n 3. Traverse/View List");
    printf("\n 4. Exit");
    printf("\n Please enter your choice: ");
    scanf("%d", &choice);
    return choice;
}

void main() {
    printf("Circular Linked List Operations\n");
    while (1) {
        switch (menu()) {
            case 1:
                insertNode();
                break;
            case 2:{
                int pos;
                printf("Enter the position to delete: ");
                scanf("%d", &pos);
                deleteNodeAtPosition(pos);
                break;
            }
            case 3:
                viewList();
                break;
            case 4:
                exit(0);
            default:
                printf("Invalid choice.\n");
        }
    }
    getch();
}

Output

Circular Linked List Operations


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 1
Enter the data you want to insert: 6


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 1
Enter the data you want to insert: 3


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 1
Enter the data you want to insert: 4


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 1
Enter the data you want to insert: 8


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 3
Values of Circular list:
6       3       4       8

***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 2
Enter the position to delete: 2
Deleted node value: 3


***** MENU *****
 1. Add value to the list
 2. Delete node from given position
 3. Traverse/View List
 4. Exit
 Please enter your choice: 4

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