Difference of two singly linked lists and display the resultant list

Problem Description

A ‘C’ program to create two singly linked lists and calculate the difference of two lists and display the resultant list.

Source Code

#include
#include

/* Link list node */
struct node
{
    int data;
    struct node* next;
};

/* A utility function to insert a node at the beginning of a linked list*/
void push (struct node** head_ref, int new_data);

/* A utilty function to chec if given data is present in a list */
int isPresent (struct node *head, int data);

/* Function to get the union of two linked lists head1 and head2 */


/* Function to get intersection of two linked lists head1 and head2 */
struct node *getDiff (struct node *head1, struct node *head2)
{
    struct node *result = NULL;
    struct node *t1 = head1;

    // Traverse list1 and search each element of it in list2. If the element
    // is present in list 2, then insert the element to result
    while (t1 != NULL)
    {
 if (!isPresent(head2, t1->data))
     push (&result, t1->data);
 t1 = t1->next;
    }

    return result;
}

/* A utility function to insert a node at the begining of a linked list*/
void push (struct node** head_ref, int new_data)
{
    /* allocate node */
    struct node* new_node =
 (struct node*) malloc(sizeof(struct node));

    /* put in the data */
    new_node->data = new_data;

    /* link the old list off the new node */
    new_node->next = (*head_ref);

    /* move the head to point to the new node */
    (*head_ref) = new_node;
}

/* A utility function to print a linked list*/
void printList (struct node *node)
{
    while (node != NULL)
    {
 printf ("%d ", node->data);
 node = node->next;
    }
}

/* A utility function that returns true if data is present in a linked list
else return false */
int is present (struct node *head, int data)
{
    struct node *t = head;
    while (t != NULL)
    {
 if (t->data == data)
     return 1;
 t = t->next;
    }
    return 0;
}

void main()
{
    /* Start with the empty list */
    struct node* head1 = NULL;
    struct node* head2 = NULL;
    struct node* difference = NULL;
     int n,num,i;
    clrscr();
    /*create a linked lits 10->15->5->20 */
    printf("\nEnter total number elements of first list : \n");
scanf("%d",&n);
for(i=0;i

Output

Enter total number elements of first list :
4

enter 1 element : 5

enter 2 element : 8

enter 3 element : 3

enter 4 element : 9

Enter total number elements of second list :
3

enter 1 element : 2

enter 2 element : 8

enter 3 element : 9

First list is
9 3 8 5
Second list is
9 8 2
Difference (elements in first list but not in second list are
5 3


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