Thread: please give me small and easy example for linked lists

I wanted this example to be as small and easy to follow as possible - adding functions can confuse things

Personally, I find that well selected and well named functions make code, even example code, much easier to follow. It beats trying to figure out why a particular block of code exists in the first place, and helps to skip over that block of code once I understand why it is there.

I decided to take a crack at it.

I am afraid this is in C, but here is a barebones example of what a list is. It only implements the simplest of list methods (add to head and print).

Code:

#include <stdio.h>
#include <stdlib.h>

struct IntList {
   int data;
   struct IntList * next;
};

/**
 * Adds data to the beginning of the list.  Modifies the structure of the list.
 * @param head The list to modify.
 * @param addMe The data to add to the list.
 */
void IntList_add2head (struct IntList ** head, int addMe) {
  
   // Create a new node to be inserted into the list. 
   struct IntList * NewNode = malloc (sizeof (struct IntList));
   NewNode->data = addMe;

   // Make the new node precede the head of the list.
   NewNode->next = *head;

   // Make the head point at the new node.
   *head = NewNode;
}

/**
 * Prints the contents of the list.
 * Output should look like...
 *    HEAD -> 5 -> 1 -> 7 -> NULL
 * @param head The list to print.
 */
void IntList_print (struct IntList * head) {
   struct IntList * curr_node;

   printf ("HEAD ->");
   // The structure of this for loop is characteristic of linked lists.
   for (curr_node = head; curr_node != NULL; curr_node = curr_node->next) {
      printf (" %d ->", curr_node->data);
   }
   printf (" NULL\n");
}

int main (void) {
   // The end of a list is always NULL.  So, an empty list is one where
   // the head is NULL.
   struct IntList * head = NULL;

   printf ("Welcome to the linked list example.\n");

   // Repeatedly prompt the user for input and add items to the list.
   for (;;) {
      int new_value;

      printf ("\n");
      IntList_print (head);
      printf ("Input a number (x to exit): ");
      if (scanf ("%d", &new_value) != 1)
         break;
      IntList_add2head (&head, new_value);
   }

   return 0;
}