C Program to Search for an Element in the Linked List using Recursion

Code:

#include   stdio.h
#include   stdlib.h

struct node
{
    int a;
    struct node *next;
};

void generate(struct node **, int);
void search(struct node *, int, int);
void delete(struct node **);

int main()
{
    struct node *head;
    int key, num;

    printf("Enter the number of nodes: ");
    scanf("%d", &num);
    generate(&head, num);
    printf("\nEnter key to search: ");
    scanf("%d", &key);
    search(head, key, num);
    delete(&head);
}

void generate(struct node **head, int num)
{
    int i;
    struct node *temp;

    for (i = 0; i < num; i++)
    {
        temp = (struct node *)malloc(sizeof(struct node));
        temp->a = rand() % num;
        printf("%d    ", temp->a);
        if (*head == NULL)
        {
            *head = temp;
            (*head)->next = NULL;
        }
        else
        {
            temp->next = *head;
            *head = temp;
        }
    }
}

void search(struct node *head, int key, int index)
{
    if (head->a == key)
    {
        printf("Key found at Position: %d\n", index);
    }
    if (head->next == NULL)
    {
        return;
    }
    search(head->next, key, index - 1);
}

void delete(struct node **head)
{
    struct node *temp;
    while (*head != NULL)
    {
        temp = *head;
        *head = (*head)->next;
        free(temp);
    }
}


Output:

Enter the number of nodes: 6
1    4    3    1    5    1
Enter key to search: 1
Key found at Position: 6
Key found at Position: 4
Key found at Position: 1



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