C Program to implement Doubly Linked List to insert and delete a node from front and display the contents of the Doubly Linked List

Program

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
struct node
{
	int info;
	struct node *rlink;
	struct node *llink;
};
typedef struct node* NODE;
NODE getnode();
NODE insert_front(NODE , int);
NODE delete_front(NODE);
void display(NODE);
void main()
{
	NODE first;
	int item, choice;
	while(1)
	{
		printf("\n");
		printf("1. Insert front\n");
		printf("2. Delete front\n");
		printf("3. Display\n");
		printf("4. Exit\n");
		scanf("%d",&choice);
		switch(choice)
		{
			case 1:
				printf("Enter item to be inserted\t");
				scanf("%d", &item);
				first = insert_front(first, item);
				break;
			case 2:
				first = delete_front(first);
				break;
			case 3:
				display(first);
		                break;
			default:
				exit(0);
		}
	}
}
NODE getnode()
{
	NODE x;
	x = (NODE) malloc(sizeof(struct node));
	if(x == NULL)
	{
		printf("Unable to create node\n");
		return;
	}
	return x;
}
NODE insert_front(NODE first, int item)
{
	NODE temp;
	temp = getnode();
	temp->info = item;
	temp->llink = NULL;
	if(first == NULL)
		return temp;	
	temp->rlink = first;
	first->llink = temp;
	return temp;
}
NODE delete_front(NODE first)
{
	NODE next;
	if(first == NULL)
	{
		printf("List is empty\n");
		return first;
	}
	if(first->rlink == NULL && first->llink == NULL)
	{
		printf("Deleted item is: %d\n", first->info);
		free(first);
		return NULL;
	}
	next = first->rlink;
	printf("Deleted item is: %d\n",first->info);
	free(first);
	return next;
}
void display(NODE first)
{
	NODE temp;
	if(first == NULL)
		printf("List is empty\n");
	printf("Contents of linked list:\n");
	temp = first;
	while(temp != NULL)
	{
		printf("%d\n", temp->info);
		temp = temp->rlink;
	}
}

Output

1. Insert front
2. Delete front
3. Display
4. Exit
2
List is empty
1. Insert front
2. Delete front
3. Display
4. Exit
1
Enter item to be inserted	40
1. Insert front
2. Delete front
3. Display
4. Exit
1
Enter item to be inserted	22
1. Insert front
2. Delete front
3. Display
4. Exit
1
Enter item to be inserted	31
1. Insert front
2. Delete front
3. Display
4. Exit
3
Contents of linked list:
31
22
40
1. Insert front
2. Delete front
3. Display
4. Exit
2
Deleted item is: 31
1. Insert front
2. Delete front
3. Display
4. Exit
2
Deleted item is: 22
1. Insert front
2. Delete front
3. Display
4. Exit
3
Contents of linked list:
40
1. Insert front
2. Delete front
3. Display
4. Exit
4