Select a random node from a singly linked list

//  C program for
//  Select a random node from a singly linked list
//  using 1/n probability
#include <stdio.h>
#include <stdlib.h>
#include <time.h> 
// Linked List LinkNode
struct LinkNode
{
    int data;
    struct LinkNode *next;
};
// Singly linked list 
struct SingleLL
{
    struct LinkNode *head;
    struct LinkNode *tail;
};
// Returns the new linked list
struct SingleLL *newLinkedList()
{
    // Create memory of head and tail Nodes
    struct SingleLL *sll = 
      (struct SingleLL *) malloc(sizeof(struct SingleLL));
    if (sll == NULL)
    {
        printf("Memory overflow\n");
    }
    else
    {
        sll->head = NULL;
    }
    return sll;
}
// Handles the request of adding new node in linked list
void addNode(struct SingleLL *sll, int data)
{
    // Create dynamic node
    struct LinkNode *node = 
      (struct LinkNode *) malloc(sizeof(struct LinkNode));
    if (node == NULL)
    {
        printf("Memory overflow to Create LinkNode\n");
        return;
    }
    else
    {
        // Set initial node value
        node->data = data;
        node->next = NULL;
    }
    if (sll->head == NULL)
    {
        sll->head = node;
    }
    else
    {
        sll->tail->next = node;
    }
    sll->tail = node;
}
// Display linked list element
void display(struct LinkNode *node)
{
    if (node == NULL)
    {
        return;
    }
    struct LinkNode *temp = node;
    // iterating linked list elements
    while (temp != NULL)
    {
        printf(" %d →", temp->data);
        // Visit to next node
        temp = temp->next;
    }
    printf(" NULL\n");
}
void randomNode(struct LinkNode *node)
{


    struct LinkNode * temp = node;

    struct LinkNode * result = node;

    int n = 2;
    
    while(temp != NULL)
    {
        if(rand() % n == 0)
        {
            // Get new resultant node
            result = temp;
        }
        // visit to next node
        temp = temp -> next;

        // increase the value of n by one
        n++;
    }
    
    if(result==NULL)
    {
        printf("\n None \n");
       
    }
    else
    {
        printf(" Result : %d \n", result->data);
    }
   
}
int main(int argc, char const *argv[])
{
    srand(time(NULL)); 

    struct SingleLL *sll1 = newLinkedList();
    struct SingleLL *sll2 = newLinkedList();
    // First linked list
    //  5 → 2 → -2 → 1 → 3 → 6 → NULL
    addNode(sll1, 5);
    addNode(sll1, 2);
    addNode(sll1, -2);
    addNode(sll1, 1);
    addNode(sll1, 3);
    addNode(sll1, 6);
    // Second linked list
    //  -1 → 7 → 5 → 8 → 9 → -9 → 10 → NULL
    addNode(sll2, -1);
    addNode(sll2, 7);
    addNode(sll2, 5);
    addNode(sll2, 8);
    addNode(sll2, 9);
    addNode(sll2, -9);
    addNode(sll2, 10);
    // Test in first LL
    display(sll1->head);
    randomNode(sll1->head);
    randomNode(sll1->head);
    randomNode(sll1->head);
    // Test in second LL
    display(sll2->head);
    randomNode(sll2->head);
    randomNode(sll2->head);

    return 0;
}

Output

 5 → 2 → -2 → 1 → 3 → 6 → NULL
 Result : 5
 Result : 1
 Result : 2
 -1 → 7 → 5 → 8 → 9 → -9 → 10 → NULL
 Result : 9
 Result : -1