It's a linked list. Of numbers. Yay. At least it can reverse itself in O(N) time.

linkedlist.c

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

#define null 0

typedef struct _node {
  int value;
  struct _node *next;
} node;

node *push (node *head, node *new);
node *pop (node *head);
node *reverse (node *head);
void printl(node *head);

int main(int argc, char *argv[]) {
  int i;
  node *head, *new;

  if(argc > 1) {
    i = atoi(argv[1]);
  } else {
    i = 6;
  }

  head = null;
  for(; i > 0; i--) {
    new = malloc(sizeof(node));
    new->value = i;
    head = push(head, new);
  }

  printf("Before:\n");
  printl(head);
  printf("\nAfter:\n");
  head = reverse(head);
  printl(head);
}

node *push (node *head, node *new) {
  new->next = head;
  return new;
}

node *pop (node *head) {
  node *curr = head;
  head = curr->next;
  return curr;
}

node *reverse (node *head) {
  node *prev, *curr, *next;

  unsigned int iterations = 0;
  curr = head;
  prev = null;
  while(curr) {
    iterations++;
    next = curr->next;
    curr->next = prev;
    prev = curr;
    curr = next;
  }
  printf("Reversed list in %u iterations\n", iterations);

  return prev;
}

void printl(node *head) {
  for(;head;head = head->next) {
    printf(" %-2d (0x%08X)\n", head->value, (unsigned int)head);
    if(head->next)
      printf(" |  \n");
  }
}