Program to reverse a linked list

Write a program to reverse a linked list

#include "stdio.h"

#include "stdlib.h"

#define MAX 10 /* max of 10 elements */

struct lnode

{

            int number;

            struct lnode *next;

};

/* add a lnode at the beginning of the list */

void llist_add_begin(struct lnode **n, int val);

/* reverse the whole list */

void llist_reverse(struct lnode **n);

/* display the whole linked list */

void llist_display(struct lnode *n);

int main(void)

{

            struct lnode *new = NULL;

            int i = 0;

            /* insert some numbers */

            for(i = 0; i <= MAX; i++)

                        llist_add_begin(&new, i);

           

            printf("linked list before reversal:");

            llist_display(new);

            llist_reverse(&new);

            printf("linked list after reversal:");

            llist_display(new);

            return 0;

}

/* add a lnode at the beginning of the list */

void llist_add_begin(struct lnode **n, int val)

{

            struct lnode *temp = NULL;

           

            /* add new node */

            temp = malloc(sizeof(struct lnode));

            temp->number = val;

            temp->next = *n;

            *n = temp;

}

/* reverse the whole list */

void llist_reverse(struct lnode **n)

{

            struct lnode *a = NULL;

            struct lnode *b = NULL;

            struct lnode *c = NULL;

            a = *n, b = NULL;

           

            while(a != NULL)

            {

                        c = b, b = a, a = a->next;

                        b->next = c;

            }

            *n = b;

}

/* display the whole linked list */

void llist_display(struct lnode *n)

{

            while(n != NULL)

                        printf(" %d", n->number), n = n->next;

            printf("\n");

}