Project 1 - Creation of user defined data type to implement the user interfaces for working with ‘Set’ (Mathematical Set theory)

Header File : list.h

#ifndef LIST_H_
#define LIST_H_
#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
typedef struct node
{
	int data;
	struct node *next;
}Node;
static Node *head1,*head2,*head_union,*head_intersection,*newnode,*tail,*res_intersection;
Node *insert_node(Node *head_ref, int n);
void display_list(Node *head_ref);
Node *get_union(Node *head_pointer1, Node *head_pointer2);
Node *get_intersection(Node *head_pointer1,Node *head_pointer2);
int compare(Node *head,int data);


#endif /* LIST_H_ */

#include"list.h"
void display_list(Node *head_ref)
{
	if(head_ref==0)//if statement if user dose not enters any number the it will show the massagelist is empty//
	{
		printf(" list is empty");
	}
	else
	{
		tail=head_ref;
		while(tail !=0)
		{
			printf("%d", tail->data);
			tail=tail->next;
		}
		tail=newnode;
	}
}
Node *insert_node(Node *head_ref,int n)
{
	printf("\nInserting Element at the beginning...\n");
	newnode=(Node*)malloc(sizeof(Node));
	printf("Address of created newnode :%d\n",newnode);//display the address of the first list items//
	newnode->data=n;
	printf("Inserted value is :%d\n",newnode->data);//display the values of the list 1 items//
	newnode->next =head_ref;
	head_ref=newnode;
	return head_ref;
}
Node *get_union(Node *head_pointer1,Node *head_pointer2)
{
	while(head_pointer1 !=0)
	{
		head_union= insert_node(head_union,head_pointer1->data);
		head_pointer1=head_pointer1->next;
	}
	while(head_pointer2 !=0)
	{
		if(! compare(head_union,head_pointer2->data))
			head_union=insert_node(head_union,head_pointer2->data);
		head_pointer2=head_pointer2->next;
	}
	return head_union;
}
int compare(Node *head,int data)
{
	while(head != NULL)
	{
		if(head->data == data)
			return 1;
		head = head->next;
	}
	return 0;
}
Node *get_intersection(Node *head_pointer1,Node*head_pointer2)
{
	while (head_pointer1 !=0)
	{
		if(compare(head_pointer2,head_pointer1->data))
			head_intersection = insert_node(head_intersection,head_pointer1->data);
		head_pointer1 = head_pointer1->next;
	}
	return head_intersection;
}

Main program:

#include "list.h"

int main()
{
	int first_nodes = 0, second_nodes = 0, first_items = 0, second_items = 0;
	printf("Enter the number of Nodes in the first List:");
	fflush(stdout);
	scanf("%d",&first_nodes);
	printf("Enter %d the elements:",first_nodes);
	for(int i = 0; i<first_nodes;i++)
	{
		fflush(stdout);
		scanf("%d",&first_items);
		head1=insert_node(head1,first_items);
	}
	display_list(head1);
	printf("\nEnter the number of Nodes in second List:");
	fflush(stdout);
	scanf("%d",&second_nodes);
	printf("Enter %d the elements:",second_nodes);
	for(int i=0;i<second_nodes;i++)
	{
		fflush(stdout);
		scanf("%d",&second_items);
		head2=insert_node(head2,second_items);
	}
	display_list(head2);
	res_union = get_union(head1,head2);
#ifdef DEBUG_MAIN
	printf("\nValue of Head1 and Head2 :%d %d",head1,head2);
#endif
#ifdef DEBUG_MAIN
	printf("\nValue of Head1 and Head2 after performing union :%d %d",head1,head2);
	printf("Value of res_union :%d\n",res_union);
#endif
	printf("Here is the result of union: ");
	display_list(res_union);
	res_intersection = get_intersection(head1,head2);
#ifdef DEBUG_MAIN
	printf("\nValue of Head1 and Head2 after performing union :%d %d",head1,head2);
	printf("Value of res_intersection :%d\n",res_intersection);
#endif
	printf("Here is the result of intersection: ");
	display_list(res_intersection);
}