Program - 6.c

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

struct node
{
    int rollno;
    char name[15];
    struct node *nxt;
} * last, *newnode, *prenode, *ptr;

void addfront()
{
    if (last == NULL)
    {
        last = (struct node *)malloc(sizeof(struct node));
        printf("Enter Roll No. : ");
        scanf("%d", &last->rollno);
        printf("Enter Name : ");
        scanf("%s", &last->name);
        last->nxt = last;
        prenode = last;
    }
    else
    {
        newnode = (struct node *)malloc(sizeof(struct node));
        printf("\nEnter Roll No. : ");
        scanf("%d", &newnode->rollno);
        printf("Enter Name : ");
        scanf("%s", &newnode->name);
        newnode->nxt = prenode;
        last->nxt = newnode;
        prenode = newnode;
    }
}

void displaycircularlist()
{
    if (last == NULL)
    {
        printf("--------------------------------------\n");
        printf("List is empty\n");
        printf("--------------------------------------\n");
    }
    else
    {
        int i = 1;
        ptr = last->nxt;
        printf("\n\nLinked list is :-\n\n");
        printf("-------------------------------------------------------\n");
        do
        {
            printf("Node - %d : Roll No. - %d", i, ptr->rollno);
            printf("\n         : Name - %s", ptr->name);
            printf("\n         : Address - %d", ptr);
            printf("\n         : Next - %d \n", ptr->nxt);
            printf("-------------------------------------------------------\n");
            ptr = ptr->nxt;
            i++;
        } while (ptr != prenode);
    }
}

int deleteend()
{
    if (last == NULL)
    {
        printf("--------------------------------------\n");
        printf("List is empty\n");
        printf("--------------------------------------\n");
        
        return 0;
    }
    else
    {
        if (last->nxt == last)
        {
            last = NULL;
        }
        else
        {
            ptr = last->nxt;
            do
            {
                ptr = ptr->nxt;
                if (ptr->nxt == last)
                {
                    ptr->nxt = last->nxt;
                    free(last);
                    last = ptr;
                    break;
                }
            } while (ptr != prenode);
        }

        printf("\n-------------------------------------------\n");
        printf("Deleted Successfully.");
        printf("\n-------------------------------------------\n");
    }
}

void main()
{
    int choice;
    printf("\n\t -: Student Information :-");
    do
    {
        printf("\n\n-------------------------------------------\n");
        printf("\t\t-: Menu :-\n");
        printf("-------------------------------------------\n\n");
        printf("1. Add Node at Front\n2. Diaplay Circular List\n");
        printf("3. Delete Node from End\n4. Exit\n");
        printf("\nEnter choice no. : ");
        scanf("%d", &choice);
        switch (choice)
        {
        case 1:
            addfront();
            printf("\n-------------------------------------------\n");
            printf("Added Successfully.");
            printf("\n-------------------------------------------\n");
            break;
        case 2:
            displaycircularlist();
            break;
        case 3:
            deleteend();
            break;
        case 4:
            break;
        default:
            printf("\nPlease enter valid choice number !!!");
        }
    } while (choice != 4);

    printf("\nPress any key to EXIT ...");
    getch();
}