Umesh Chandra

Linked list is a linear data structure that includes a series of connected nodes. Here each node stores the data and the address of the next node.

Code:

#include<stdio.h>
#include<stdlib.h>
#include<limits.h>
struct Node
{
    int data;
    struct Node *next;
}*first = NULL;

void create(int A[], int n)
{
    struct Node *t, *last;
    first = (struct Node *)malloc(sizeof(struct Node));
    first->data = A[0];
    first->next = NULL;
    last = first;
    for(int i=1; i<n; i++)
    {
        t = (struct Node *)malloc(sizeof(struct Node));
        t->data = A[i];
        t->next = NULL;
        last->next = t;
        last = t;
    }
}

int count(struct Node *p)
{
    int c = 0;
    while(p)
    {
        c = c + 1;
        p = p->next;
    }
    return c;
}

void Delete(struct Node *p, int pos)
{
    struct Node *q = NULL;
    if(pos < 1 || pos > count(p))
    {
        printf("Cannot perform Deletion");
    }
    if(pos == 1)
    {
        q = first;
        first = first->next;
        free(q);
    }
    else
    {
        for(int i=0; i<pos-1; i++)
        {
            q = p;
            p = p->next;
        }
        q->next = p->next;
        free(p);
    }
}

void Display(struct Node *p)
{
    while(p)
    {
        printf("%d ", p->data);
        p = p->next;
    }
}

int IsSorted(struct Node *p)
{
    int x = INT_MIN;
    p = first;
    while(p)
    {
        if(p->data < x)
        {
            return 0;
        }
        else
        {
            x = p->data;
            p = p->next;
        }
    }
    return 1;
}

void Reverse(struct Node *p)
{
    int *A;
    struct Node *q = p;
    A = (int *)malloc(sizeof(int)*count(p));
    int i=0;
    while(q)
    {
        A[i] = q->data;
        i++;
        q = q->next;
    }
    q = p;
    i--;
    while(q)
    {
        q->data = A[i];
        i--;
        q = q->next;
    }
}

void Reverse1(struct Node *p)
{
    struct Node *q = NULL;
    struct Node *r = NULL;
    while(p)
    {
        r = q;
        q = p;
        p = p->next;
        q->next = r;
    }
    first = q;
}

int main()
{
    struct Node *p = first;
    int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int n = 10;
    create(A, n);
    printf("%d ", IsSorted(p));
    printf("\n");
    Delete(first, 4);
    Display(first);
    printf("\n");
    Reverse(first);
    Display(first);
    Reverse1(first);
    printf("\n");
    Display(first);
}