Ds

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

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

struct node *getnode()
{
    struct node *p;
    p = (struct node *)malloc(sizeof(struct node));
    if (p == NULL)
        printf("\nNEW NODE CANNOT BE GENERATED");
    else
        return (p);
}

void insert_start(struct node **q)
{
    struct node *p;
    p = getnode();
    if (p != NULL)
    {
        printf("\nENTER THE NODE INFO VALUE:");
        scanf("%d", &p->info);
        p->next = *q;
        *q = p;
    }
}

void delete_start(struct node **q)
{
    int x;
    struct node *p;
    if (*q == NULL)
        printf("\nLINK LIST IS EMPTY");
    else
    {
        p = *q;
        x = p->info;
        *q = p->next;
        free(p);
    }
}

void delete_q(struct node **q)
{
    int x;
    struct node *p;
    if (*q == NULL)
        printf("\nQUEUE IS EMPTY");
    else
    {
        p = *q;
        x = p->info;
        *q = p->next;
        free(p);
    }
}

void pop(struct node **q)
{
    int x;
    struct node *p;
    if (*q == NULL)
        printf("\nLINK LIST IS EMPTY");
    else
    {
        p = *q;
        x = p->info;
        printf("%d is deleted",x);
        *q = p->next;
        free(p);
    }
}

void insert_last(struct node **q)
{
    struct node *p, *temp;
    p = getnode();
    if (p != NULL)
    {
        printf("\nENTER THE NODE INFO VALUE:");
        scanf("%d", &p->info);
        temp = *q;
        if (*q == NULL)
        {
            *q = p;
            p->next = NULL;
        }
        else
        {
            while (temp->next != NULL)
                temp = temp->next;
            p->next = temp->next;
            temp->next = p;
        }
    }
}

void insert_at(struct node **q)
{
    int loc, i;
    struct node *p,*t=*q;
    printf("\nENTER THE LOCATION OF A NODE:");
    scanf("%d", &loc);
    for (i = 1; i <= loc; i++)
        t= t->next;

    if (t== NULL)
        printf("\nYOU HAVE LESS NUMBER OF NODES:");
    else
    {
        p = getnode();
        if (p != NULL)
        {
            printf("\nENTER THE NODE INFO VALUE:");
            scanf("%d", &p->info);
            p->next = t->next;
            t->next = p;
        }
    }
}

void delete_at(struct node **q)
{
    struct node *prev, *p;
    int i, x, loc;
    if (*q == NULL)
        printf("\nLINK LIST IS EMPTY");
    else
    {
        printf("\nENTER THE LOCATION:");
        scanf("%d", &loc);
        p = *q;
        if (loc == 1)
        {
            x = p->info;
            *q = p->next;
        }
        else
        {
            for (i = 1; i < loc; i++)
            {
                prev = p;
                p = p->next;
            }
            if (p == NULL)
                printf("\nLINK LIST HAS LESS NUMBER OF NODES");
            else
            {
                x = p->info;
                prev->next = p->next;
                free(q);
            }
        }
    }
}

void delete_last(struct node **q)
{
    struct node *p = *q, *prev;
    //int x;
    if (*q == NULL){
        printf("\nLINK LIST IS EMPTY");
        return;
    }
    if (p->next == NULL)
    {
        printf("%d deleted",p->info);
        *q=NULL;
        return;
    }
    else
    {
        while (p->next != NULL)
        {
            prev = p;
            p = p->next;
        }
        printf("%d is deleted",p->info);
        prev->next = NULL;
        free(p);
    }
}

void traverse(struct node *q)
{
    if (q == NULL)
        printf("\nLINK LIST IS EMPTY");
    else
    {
        while (q != NULL)
        {
            printf("%d\t", q->info);
            q = q->next;
        }
    }
}

void count(struct node *q)
{
    int count = 0;
    if (q == NULL)
        printf("\nTHERE IS NO NODE");
    else
    {
        while (q != NULL)
        {
            count = count + 1;
            q = q->next;
        }
    }
    printf("\nNUMBER OF NODES ARE:%d", count);
}


int main()
{
    struct node *list;
    list = NULL;
    int choice;
    char ch;
    //clrscr();
    while (1)
    {
        printf("\n1.INSERT OPERTATION AT START:");
        printf("\n2.DELETE OPERATION AT START:");
        printf("\n3.INSERT OPERATION AT LAST:");
        printf("\n4.DELETE OPERTAION AT LAST:");
        printf("\n5.INSERT OPERATION AT GIVEN LOCATION:");
        printf("\n6.DELETE OPERATION AT GIVEN LOCATION:");
        printf("\n7.COUNT THE NUMBER OF NODES:");
        printf("\n8.TRAVERSE THE LINK LIST:");
        printf("\n9.PUSH OPERATION AT STACK:");
        printf("\n10.DELETE OPERATION AT STACK:");
        printf("\n11.INSERT OPERATION AT QUEUE:");
        printf("\n12.DELETE OPERATION AT QUEUE:");
        printf("\n13.EXIT:\n");
        scanf("%d", &choice);
        switch (choice)
        {
        case 1:
            insert_start(&list);
            break;
        case 2:
            delete_start(&list);
            break;
        case 3:
            insert_last(&list);
            break;
        case 4:
            delete_last(&list);
            break;
        case 5:
            insert_at(&list);
            break;
        case 6:
            delete_at(&list);
            break;
        case 7:
            count(list);
            break;
        case 8:
            traverse(list);
            break;
        case 9:
            insert_start(&list);
            break;
        case 10:
            pop(&list);
            break;
        case 11:
            insert_start(&list);
            break;
        case 12:
            delete_q(&list);
        case 13:
            exit(0);
            break;
        default:
            printf("\nWRONG CHOICE");
        }
    }
    return 0;
}