C-Collections

Java collections and lists for C

Table of Contents

• ArrayList
• LinkedList
• Iterator
• Collection
  • Swap
  • Sort & SortRangeOf
  • BinarySearch
  • Max
  • Min
  • Fill
  • Reverse
  • Rotate
• HashMap
• HashSet (TO-DO)

ArrayList

What is ArrayList?

ArrayList is a dynamic array and we do not have to specify the size while creating it, the size of the array automatically increases when we dynamically add and remove items.

Usage

• include ArrayList header file

#include "array_list.h"

• Create ArrayList struct :

struct ArrayList *list = array_list_create(); // or array_list_create2(capacity);

• Add items to the list :

array_list_add(list, "Hello");
array_list_add(list, "World");

Result :

1. Hello
2. World

• Insert item :

array_list_insert(list, "First", 0);

Result :

1. First
2. Hello
3. World

• InsertAll (Or AddAll) :

char *list2[] = {"Hi", "Hii", "Hiii"};
array_list_insertAll(list, collection_create((void **) list2, 3), 1);

Result :

1. First
2. Hi
3. Hii
4. Hiii
5. Hello
6. World

• Remove item (Or removeRange/ removeData) :

array_list_remove(list, index);

LinkedList

What is LinkedList?

A linked list is a linear data structure, in which the elements are not stored at contiguous memory locations. The elements in a linked list are linked using pointers

Usage

• include LinkedList header file

#include "linked_list.h"

• Create the Head element :

struct LinkedListNode *list = linked_list_new("Hello");

• Append

linked_list_append(linked_list_new("Test"), list);

Result: Hello -> Test

• Push

linked_list_push(linked_list_new("1", linked_list_new("2")), list);

Result: 1 -> 2 -> Hello -> Test

• Pop

linked_list_pop(list);

Result: 2 -> Hello -> Test

• Insert

linked_list_insertAt(linked_list_new("A"), list, 1);

Result: 2 -> A -> Hello -> Test

• Insert with Finder function

// -1 = insert before target
// +1 = insert after target
// +2 = insert after the next position of target, ...
int finder(struct LinkedListNode* node, int index, const void *target) {
    return strcmp(target, node->data) == 0 ? 2 : 0;
}

linked_list_insert(linked_list_new("B"), list, "A", finder);

Result: 2 -> A -> Hello -> B -> Test

• Remove

linked_list_removeAt(list, 2);

Result: 2 -> A -> B -> Test

• Connect

linked_list_connect_before(&list, linked_list_new("NEW", linked_list_new("HI")), linked_list_new("TEST"));

Result: TEST -> NEW -> HI -> 2 -> A -> B -> Test

• Check out other functions such as connect_after, pollLast, peekLast, removeRange, copy, toArray, indexOf, lastIndexOf, swap, set, find, ...

Iterator

What is Iterator?

Iterator can be used to loop through collections

Usage

#include "iterator.h"

struct Iterator *iter = collection_iterator(collection);
// struct Iterator *iter = array_list_iterator(arrayList);
// struct Iterator *iter = linked_list_iterator(linkedList);

while (iterator_has_next(iter)) {
    printf("%s -> ", (char *) iterator_next(iter));
    // iterator_remove(iter) if needed to remove the element from the collection
}
iterator_destroy(iter);

Collection

#include "collection.h"

struct Collection coll = collection_create(array, size);
// struct Collection coll = array_list_collection(arrayList);
// struct Collection coll = linked_list_collection(linkedList);

collection_sort(coll, comparator);
collection_reverse(coll);
collection_rotate(coll, 1);
void * value = collection_binarySearch(coll, key, comparator);
void * value = collection_max(coll, comparator);
void * value = collection_min(coll, comparator);
collection_fill(coll, value);

HashMap

What is HashMap?

HashMap stores the data in (Key, Value) pairs...

Usage

• include HashMap header file

#include "hash_map.h"

• Create HashMap struct :

struct HashMap *map = hash_map_create(); // or hash_map_create2(capacity);

• Put key-values :

hash_map_string_put(map, "Key1", "Item1");
hash_map_int_put(map, 2, "Item2");
hash_map_put(map, key, value);

• Get value by key :

printf("%s\n", (char *) hash_map_string_get(map, "Key1"));
printf("%s\n", (char *) hash_map_int_get(map, 2));

• Remove value by key

hash_map_int_remove(map, 2);

• Checkout other functions such as containsKey, containsValue, putAll, ...

Iterator over keys, values and entries

hash_map_entryIterator, hash_map_keyIterator and hash_map_valueIterator

struct Iterator *iter = hash_map_entryIterator(map);
while (iterator_has_next(iter)) {
    struct HashMapEntry *entry = iterator_next(iter);
    printf("Key: %s, Value: %s\n", (char *) entry->key, (char *) entry->value);
}
iterator_destroy(iter);