c_dp_linked_list

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

typedef struct node
{
  struct node * next;
  int val;
} node;

bool remove_is_5(node const *v) {
  return v->val == 5;
}

typedef bool (*remove_fn)(node const*v);

node *head = NULL;
node *tail = NULL;
int size = 0;

void Head(int val) {
   node *add = malloc(sizeof(node));
   add->val = val;
   add->next = head;
   head = add;
   if(size == 0) tail = head;
   size++;
}

void Tail(int val) {
  node *add = malloc(sizeof(node));
  add->val = val;
  tail->next = add;
  tail = add;
  if(size == 0) head = tail;
  size++;
}

void DumpLinkedList(node * ref) {
  printf("-----------------\n");
  node *it = ref;
  for(int i = 0; i < size; i++) {
    printf("%x %d\n",  it, it->val);
    it = it->next;
  }
  printf("-----------------\n");
}



void remove_if(node ** head, remove_fn rm)
{
  for (node** curr = head; *curr; )
  {
	node * entry = *curr;
	if (rm(entry))
	{
	  *curr = entry->next;
	  size--;
	  free(entry);
	}
	else
	  curr = &entry->next;
  }
}


int main() {
  Head(3);
  Head(4);
  Head(5);
  Tail(6);
  Tail(6);
  Tail(6);
  DumpLinkedList(head);
  remove_if(&head, remove_is_5);
  DumpLinkedList(head);
  return 0;
}