C Programming Code Examples

C > Linked Lists Code Examples

C Program to Find the first Common Element between the 2 given Linked Lists

C Program to Find the first Common Element between the 2 given Linked Lists

    #include <stdio.h>

    #include <stdlib.h>

    struct node

    {

        int j;

        struct node *next;

    };

    void create(struct node **);

    int find(struct node *, struct node *);

    void release(struct node **);

    void display(struct node *);

    int main()

    {

        struct node *p = NULL, *q = NULL;

        int result;

        printf("Enter data into the list\n");

        create(&p);

        printf("Enter data into the list\n");

        create(&q);

        printf("Displaying list1:\n");

        display(p);

        printf("Displaying list2:\n");

        display(q);

        result = find(p, q);

        if (result)

        {

            printf("The first matched element is %d.\n", result);

        }

        else

        {

            printf("No matching element found.\n");

        }

        release (&p);

        return 0;

    }

    int find(struct node *p, struct node *q)

    {

        struct node *temp;

        while (p != NULL)

        {

            temp = q;

            while (temp != NULL)

            {

                if (temp->j == p->j)

                {

                    return p->j;

                }

                temp = temp->next;

            }

            p = p->next;

        }

        /*Assuming 0 is not used in the list*/

        return 0;

    }

    void create(struct node **head)

    {

        int c, ch;

        struct node *temp, *rear;

        do

        {

            printf("Enter number: ");

            scanf("%d", &c);

            temp = (struct node *)malloc(sizeof(struct node));

            temp->j = c;

            temp->next = NULL;

            if (*head == NULL)

            {

                *head = temp;

            }

            else

            {

                rear->next = temp;

            }

            rear = temp;

            printf("Do you wish to continue [1/0]: ");

            scanf("%d", &ch);

        } while (ch != 0);

        printf("\n");

    }

    void display(struct node *head)

    {

        while (head != NULL)

        {

            printf("%d\t", head->j);

            head = head->next;

        }

        printf("\n");

    }

    void release(struct node **head)

    {

        struct node *temp;

        while ((*head) != NULL)

        {

            temp = *head;

            (*head) = (*head)->next;

            free(temp);

        }

    }