C Program to implement Singly Linked List to insert and delete a node from front and display the contents of the Singly List using Header Node

Program

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
struct node
{
	int info;
	struct node *link;
};
typedef struct node* NODE;
NODE getnode();
NODE insert_front(NODE , int);
NODE delete_front(NODE);
void display(NODE);
void main()
{
	NODE head;
	int choice, item;
	head = getnode();
	head->info = 0;
	head->link = NULL;
	while(1)
	{
		printf("Enter\n");
		printf("1. Insert Front\n");
		printf("2. Delete Front\n");
		printf("3. Display the list\n");
		printf("4. Exit\n");
		scanf("%d", &choice);
		switch(choice)
		{
			case 1:
				printf("Enter item to be inserted\n");
				scanf("%d", &item);
				head = insert_front(head, item);
				break;
			case 2:
				head = delete_front(head);
				break;
			case 3:
				display(head);
				break;
			default:
				exit(0);
		}
	}
}
NODE getnode()
{
	NODE x;
	x = (NODE) malloc(sizeof(struct node));
	if(x == NULL)
	{
		printf("Node creation error\n");
		return NULL;
	}
	return x;
}
NODE insert_front(NODE head , int item)
{
	NODE temp, next;
	temp = getnode();
	temp->info = item;
	next = head->link;
	head->link = temp;
	temp->link = next;
	head->info += 1;
	return head;
}
NODE delete_front(NODE head)
{
	NODE temp, next;
	if(head->link == NULL)
	{
		printf("Cannot delete. Empty List\n");
		return head;
	}
	temp = head->link;
	next = temp->link;
	head->link = next;
	head->info -= 1;
	printf("Deleted node is %d\n", temp->info);
	free(temp);
	return head;
}
void display(NODE head)
{
	NODE temp;
	if(head->link == NULL)
	{
		printf("Cannot print. Empty list\n");
		return;
	}
	temp = head->link;
	printf("Contents of linked list is:\n");
	while(temp != NULL)
	{
		printf("%d\t", temp->info);
		temp = temp->link;
	}
	printf("\nNode count:\t%d\n", head->info);
}

Output

Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
1
Enter item to be inserted
10
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
1
Enter item to be inserted
20
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
3
Contents of linked list is:
20	10	
Node count:	2
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
1
Enter item to be inserted
30
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
1
Enter item to be inserted
40
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
3
Contents of linked list is:
40	30	20	10	
Node count:	4
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
2
Deleted node is 40
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
2
Deleted node is 30
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
2
Deleted node is 20
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
3
Contents of linked list is:
10	
Node count:	1
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
2
Deleted node is 10
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
2
Cannot delete. Empty List
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
3
Cannot print. Empty list
Enter
1. Insert Front
2. Delete Front
3. Display the list
4. Exit
4