circular_linklist.c

#include <stdio.h>
#include <stdlib.h>
struct Node 
{
    int data;
    struct Node *next;
};
struct Node *head = NULL;
// Function to insert a node at the beginning of the Circular linked list
void insertAtBeginning(int value) 
{
    struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));
    newNode->data = value;
    if (head == NULL) 
	{
        newNode->next = newNode;
        head = newNode;
    } 
	else 
	{
        struct Node *temp = head;
        while (temp->next != head) 
		{
            temp = temp->next;
        }
        newNode->next = head;
        temp->next = newNode;
        head = newNode;
    }
    printf("Node inserted at the Beginning.\n");
}
// Function to insert a node at a specific position in the Circular linked list
void insertAtPosition(int value, int position) 
{
    if (position < 1) 
	{
        printf("Invalid Position!\n");
        return;
    }
    if (position == 1) 
	{
        insertAtBeginning(value);
        return;
    }
    struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));
    newNode->data = value;
    struct Node *temp = head;
    int currentPosition = 1;
    while (currentPosition < position - 1 && temp->next != head) 
	{
        temp = temp->next;
        currentPosition++;
    }
    if (currentPosition != position - 1) 
	{
        printf("Invalid Position!\n");
        free(newNode);
        return;
    }
    newNode->next = temp->next;
    temp->next = newNode;
    printf("Node inserted at the Position.\n");
}
// Function to insert a node at the end of the Circular linked list
void insertAtEnd(int value)
{
    struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));
    newNode->data = value;
    if (head == NULL) 
	{
        newNode->next = newNode;
        head = newNode;
    } 
	else 
	{
        struct Node *temp = head;
        while (temp->next != head) 
		{
            temp = temp->next;
        }
        newNode->next = head;
        temp->next = newNode;
    }
    printf("Node inserted at the End.\n");
}
// Function to delete a node from the beginning of the Circular linked list
void deleteFromBeginning()
{
    if (head == NULL) 
	{
        printf("List is Epty. Nothing to Delete!\n");
        return;
    }
    struct Node *temp = head;
    if (head->next == head) 
	{
        head = NULL;
    } 
	else 
	{
        struct Node *last = head;
        while (last->next != head) 
		{
            last = last->next;
        }
        head = head->next;
        last->next = head;
    }
    free(temp);
    printf("Node deleted from Beginning.\n");
}
// Function to delete a node from a specific position in the Circular linked list
void deleteFromPosition(int position)
{
    if (head == NULL) 
	{
        printf("List is Empty. Nothing to Delete!\n");
        return;
    }
    if (position < 1) 
	{
        printf("Invalid Position!\n");
        return;
    }
    if (position == 1) 
	{
        deleteFromBeginning();
        return;
    }
    struct Node *temp = head;
    struct Node *prev = NULL;
    int currentPosition = 1;
    while (currentPosition < position && temp->next != head) 
	{
        prev = temp;
        temp = temp->next;
        currentPosition++;
    }
    if (currentPosition != position) 
	{
        printf("Invalid Position!\n");
        return;
    }
    prev->next = temp->next;
    free(temp);
    printf("Node deleted from the Position.\n");
}
// Function to delete a node from the end of the Circular linked list
void deleteFromEnd() 
{
    if (head == NULL) 
	{
        printf("List is Empty. Nothing to Delete!\n");
        return;
    }
    struct Node *temp = head;
    struct Node *prev = NULL;
    while (temp->next != head) 
	{
        prev = temp;
        temp = temp->next;
    }
    if (prev == NULL) 
	{
        head = NULL;
    } 
	else 
	{
        prev->next = head;
    }
    free(temp);
    printf("Node deleted from the End.\n");
}
// Function to display all the nodes in the Circular linked list
void display() 
{
    if (head == NULL) 
	{
        printf("List is Empty!\n");
        return;
    }
    struct Node *temp = head;
    do 
	{
        printf("%d -> ", temp->data);
        temp = temp->next;
    } 
	while (temp != head);
    printf("\n");
}
int main() 
{
    int choice, value, position;
    while (1) 
	{
        printf("Circular Linked List Operations:-\n");
        printf("1. Insert at the beginning\n");
        printf("2. Insert at a specific position\n");
        printf("3. Insert at the end\n");
        printf("4. Delete from the beginning\n");
        printf("5. Delete from a specific position\n");
        printf("6. Delete from the end\n");
        printf("7. Display all nodes\n");
        printf("8. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice)
		{
            case 1:
                printf("Enter value to insert: ");
                scanf("%d", &value);
                insertAtBeginning(value);
                break;
            case 2:
                printf("Enter value to insert: ");
                scanf("%d", &value);
                printf("Enter position: ");
                scanf("%d", &position);
                insertAtPosition(value, position);
                break;
            case 3:
                printf("Enter value to insert: ");
                scanf("%d", &value);
                insertAtEnd(value);
                break;
            case 4:
                deleteFromBeginning();
                break;
            case 5:
                printf("Enter position to delete: ");
                scanf("%d", &position);
                deleteFromPosition(position);
                break;
            case 6:
                deleteFromEnd();
                break;
            case 7:
                display();
                break;
            case 8:
                exit(0);
            default:
                printf("Invalid choice. Please enter a valid option.\n");
        }
    }
    return 0;
}