Simple LinkedList written in C

linkedList.c

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

/* List Structure */
/* int ListStruct */
#define TYPE int

typedef struct _listNode {
  struct _listNode* prevNode;
  struct _listNode* nextNode;
  TYPE value;
} listNode;

typedef struct _list{
  listNode* firstNode;
  listNode* lastNode;
  listNode* thisNode;
} list;

void addNode(list* parentList, TYPE newValue){
  listNode* newNode = (listNode*)malloc(sizeof(listNode));
  newNode->value = newValue;
  newNode->nextNode = NULL;
  
  if(parentList->lastNode != NULL){
    parentList->lastNode->nextNode = newNode;
    newNode->prevNode    = parentList->lastNode;
    parentList->lastNode = newNode;
  } else {
    parentList->firstNode = parentList->lastNode = newNode;
    newNode->prevNode = NULL;
  }
}

void freeList(list* parentList){
  for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
    parentList->thisNode = parentList->thisNode->nextNode)
    free(parentList->thisNode);
}

unsigned long listLength(list* parentList){
  unsigned long arraySize = 0;
  for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->nextNode)
    arraySize++;
  return arraySize;
}

TYPE* toArray(list* parentList){
  int* array;
  int count;
  unsigned long arraySize;
  
  arraySize = listLength(parentList);
  count     = 0;

  array = (TYPE*)malloc(sizeof(TYPE) * arraySize);
  for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->nextNode)
    array[count++] = parentList->thisNode->value;

  return array;
}

TYPE* toReArray(list* parentList){
  int* array;
  int count;
  unsigned long arraySize;
  
  arraySize = listLength(parentList);
  count     = 0;

  array = (TYPE*)malloc(sizeof(TYPE) * arraySize);
  for(parentList->thisNode = parentList->lastNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->prevNode)
    array[count++] = parentList->thisNode->value;
  
  return array;
}

bool findNode(list* parentList, TYPE key){
  for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->nextNode)
    if(parentList->thisNode->value == key)
      return true;
  return false;
}

listNode* pickupNode(list* parentList, TYPE key){
  listNode* returnNode;
   for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->nextNode)
     if(parentList->thisNode->value == key)
       returnNode = parentList->thisNode;
  return returnNode;
}

void printAll(list* parentList){
  for(parentList->thisNode = parentList->firstNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->nextNode)
    printf("%d\n", parentList->thisNode->value);
}

void printReAll(list* parentList){
  for(parentList->thisNode = parentList->lastNode; parentList->thisNode != NULL;
      parentList->thisNode = parentList->thisNode->prevNode)
    printf("%d\n", parentList->thisNode->value);
}
/* end of list struct implementation */

int main(){
  int* array;
  int* array2;
  int i;
  list intList = {};
  //add node
  for(i = 0; i < 5; i++)
    addNode(&intList, i);

  printf("printAll------\n");
  printAll(&intList);
  printf("printReAll------\n");
  printReAll(&intList);

  printf("toArray test------\n");
  array = toArray(&intList);
  for(i = 0; i < listLength(&intList); i++)
    printf("%d\n", array[i]);
  
  printf("toReArray test------\n");
  array2 = toReArray(&intList);
  for(i = 0; i < listLength(&intList); i++)
    printf("%d\n", array2[i]);

  printf("findNode test------\n");
  if(findNode(&intList, 2))
    printf("true\n");
  else
    printf("false\n");
  
  printf("pickupNode test------\n");
  printf("%d\n", pickupNode(&intList, 2)->value);

  freeList(&intList);
  return 0;
}