This C program accepts two singly linked lists as input and prints a list containing only the elements common to both lists. It contains functions to create and display the lists, as well as a common_elements function that iterates through both lists, comparing elements and printing any matches. The main function calls list_create twice to populate the lists, display_list to output the lists, and common_elements to find and print the common elements.

1. S3-2
Write a program in ‘C’ language that accepts two singly linked lists A and B as
input.
Now, print a singly linked list that consists of only those elements,
which are common to both A and B.
# include<stdio.h>
# include<conio.h>
struct student
{
int rollno;
struct student *next;
} *s1, *s2;
/*creation of linked list*/
void list_create (struct student *s1)
{
printf ("enter roll number(-1 to stop)") ;
scanf("%d", & s1->rollno);
if (s1->rollno != -1) /* ‘-1’ is entered to stop*/
{
s1->next = (struct student*) malloc (sizeof (struct student));
list_create (s1->next);
}
else
s1->next = NULL;
return;
}
/*display the list*/
void display_list (struct student *s1)
{
if (s1->next != NULL)
{
printf ("%dn", s1->rollno);
display_list (s1->next);
}
}
/* function to print common elements */
void common_elements (struct student *s1, struct student * s2)
{
int flag = 0;
struct student *temp = s2;
/* temp is to store the initial node of s2*)*/
printf ("common elements n");
while (s1->next !=NULL) /*repeat till the end of s1*/
{
while (s2->next !=NULL)/* This loop is repeated that many times the number of
nodes in s1x s2
*/
{
if (s1->rollno==s2->rollno)
{
flag=1;
printf ("%dn", s1->rollno);
/*flag is set to show that an equal roll number is met*/
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2. S3-2
}
s2=s2->next;
}
s1=s1->next;
s2=temp; /* s2 is to be started again from beginning when s1=s1®next */
}
if (flag==0)
printf ("no common elements");
}
void main ()
{
s1=(struct student*) malloc (sizeof (struct student));
s2=(struct student*) malloc (sizeof (struct student));
printf("Enter the elements to first list:n");
list_create (s1);
printf ("elements in first list n");
display_list(s1);
getch();
printf("enter elements to second listn");
list_create (s2); /* creating second list */
printf("elements in second list n");
display_list (s2);
/*printing common elements */
common_elements(s1, s2);
getch();
}
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