/* Some dynamic allocation of structures */

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

int main()
{

	struct datalist
		{
			char name[20];
			struct datalist *next;
		};

	struct datalist *head, *current, *new;

	int i;

	/* set up an initial list */
	head = (struct datalist *)malloc(sizeof(struct datalist));
	sprintf(head->name, "The number %d", 0);
	current = head;

	for (i=1; i<10; i++)
	{
		new = (struct datalist *)malloc(sizeof(struct datalist));
		sprintf(new->name, "The number %d", i);
		current->next = new;
		new->next = NULL;
		current = new;
	}

	/* print out the list */
	printf("The initial list is:\n");

	current = head;
	while (current->next != NULL)
	{
		printf("%s\n", current->name);
		current = current->next;
	}

	/* now let's make a new entry */
	new = (struct datalist *)malloc(sizeof(struct datalist));
	sprintf(new->name, "Hi There!");

	/* find a spot to insert it */
	current = head;
	for (i=0; i<3; i++)
		current = current->next;

	/* insert the new entry at this point */
	new->next = current->next;
	current->next = new;

	/* and print 'em out again */
	printf("\n\nThe new list:\n");

	current = head;
	while (current->next != NULL)
	{
		printf("%s\n", current->name);
		current = current->next;
	}

	/* finally, let's delete an item from the list */
	current = head;
	for (i=0; i<3; i++)
		current = current->next;

	/* set new to point to the item after current */
	new = current->next;

	/* now repoint current's next pointer to the item after new */
	current->next = new->next;

	/* now that it's out of the linked list, we'll free the memory used
	   by the now-unused list item */
	free(new);

	/* finally, print the list out once again */
	printf("\n\nThe list with item deleted is:\n");
	current = head;
	while (current-> next != NULL)
	{
		printf("%s\n", current->name);
		current = current->next;
	}

}