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

Program

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
struct node
{
	int info;
	struct node *link;
};
typedef struct node* NODE;
NODE getnode()
{
	NODE x;
	x = (NODE) malloc(sizeof(struct node));
	if(x == NULL)
	{
		printf("Cannot create node\n");
		return NULL;
	}
	return x;
}
void freenode(NODE x)
{
	free(x);
}
NODE insert_front(int item, NODE last)
{
	NODE temp;
	temp = getnode();	
	temp->info = item;
	if(last == NULL)
	{
		last = temp;
		last->link = last;
		return last;
	}
	else
		temp->link = last->link;
	last->link = temp;
	return last;
}
NODE delete_front(NODE last)
{
	NODE first;
	if(last == NULL)
	{
		printf("List is empty. Deletion not possible\n");
		return NULL;
	}
	if(last->link == last)
	{
		printf("The item deleted is %d\n", last->info);
		freenode(last);
		return NULL;
	}
	first = last->link;
	printf("Item deleted is %d\n", first->info);
	last->link = first->link;
	freenode(first);
	return last;
}
void display(NODE last)
{
	NODE cur;
	if(last == NULL)
	{
		printf("List is empty. Cannot print\n");
		return;
	}
	if(last->link == last)
	{
		printf("%d\n", last->info);
		return;
	}
	cur = last;
	while(cur->link != last )
	{
		cur = cur->link;
		printf("%d\n", cur->info);
	}
	cur = cur->link;
	printf("%d\n", cur->info);
}
void main()
{
	int choice, item;
	NODE last;
	last = NULL;
	printf("Circular Linked List\n");
	printf("Insert and Delete to the front of the list\n");
	for(;;)
	{
		printf("1. Insert Front\n2. Delete Front\n3. Display\n4. Exit\n");
		printf("Choice:\t");
		scanf("%d", &choice);
		switch(choice)
		{
			case 1:
				printf("Enter the item to be inserted:\t");
				scanf("%d", &item);
				last = insert_front(item, last);
				break;
			case 2:
				last = delete_front(last);
				break;
			case 3:
				display(last);
				break;
			default:
				exit(0);
		}
	}
}

Output

Circular Linked List
Insert and Delete to the front of the list
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	2
List is empty. Deletion not possible
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	1
Enter the item to be inserted:	1
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	1
Enter the item to be inserted:	21
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	1
Enter the item to be inserted:	3
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	3
3
21
1
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	1
Enter the item to be inserted:	20
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	1
Enter the item to be inserted:	17
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	3
17
20
3
21
1
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	2
Item deleted is 17
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	3
20
3
21
1
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	2
Item deleted is 20
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	3
3
21
1
1. Insert Front
2. Delete Front
3. Display
4. Exit
Choice:	4