diff --git a/cv4/list_ops.c b/cv4/list_ops.c
index d62348e..d27b5de 100644
--- a/cv4/list_ops.c
+++ b/cv4/list_ops.c
@@ -19,3 +19,136 @@ list_t *new_list(size_t length, list_element_t elements[]) {
 
     return newList;
 }
+
+list_t *append_list(list_t *list1, list_t *list2) {
+    if (list1 == NULL) {
+        return (list2 != NULL) ? new_list(list2->length, list2->elements) : NULL;
+    }
+
+    if (list2 == NULL) {
+        return new_list(list1->length, list1->elements);
+    }
+
+    size_t totalSize = sizeof(list_t) + (list1->length + list2->length) * sizeof(list_element_t);
+
+    list_t *newList = (list_t *)malloc(totalSize);
+
+    if (!newList) {
+        return NULL;
+    }
+
+    newList->length = list1->length + list2->length;
+
+    for (size_t i = 0; i < list1->length; ++i) {
+        newList->elements[i] = list1->elements[i];
+    }
+
+    for (size_t i = 0; i < list2->length; ++i) {
+        newList->elements[list1->length + i] = list2->elements[i];
+    }
+
+    return newList;
+}
+
+list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
+    if (list == NULL || filter == NULL) {
+        return NULL;
+    }
+
+    size_t count = 0;
+    for (size_t i = 0; i < list->length; ++i) {
+        if (filter(list->elements[i])) {
+            count++;
+        }
+    }
+
+    if (count == 0) {
+        return new_list(0, NULL);
+    }
+
+    size_t totalSize = sizeof(list_t) + count * sizeof(list_element_t);
+    list_t *filtered_list = (list_t *)malloc(totalSize);
+
+    if (!filtered_list) {
+        return NULL;
+    }
+
+    filtered_list->length = count;
+
+    size_t filteredIndex = 0;
+    for (size_t i = 0; i < list->length; ++i) {
+        if (filter(list->elements[i])) {
+            filtered_list->elements[filteredIndex] = list->elements[i];
+            filteredIndex++;
+        }
+    }
+
+    return filtered_list;
+}
+
+size_t length_list(list_t *list) {
+    if (list == NULL) {
+        return 0;
+    }
+
+    return list->length;
+}
+
+list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
+    if (list == NULL || map == NULL) {
+        return NULL;
+    }
+
+    list_t *mapped_list = new_list(list->length, NULL);
+
+    if (mapped_list == NULL) {
+        return NULL;
+    }
+
+    for (size_t i = 0; i < list->length; ++i) {
+        mapped_list->elements[i] = map(list->elements[i]);
+    }
+
+    return mapped_list;
+}
+
+
+list_element_t foldl_list(list_t *list, list_element_t initial,
+                          list_element_t (*foldl)(list_element_t,
+                                                  list_element_t)) {
+    if (list == NULL || foldl == NULL) {
+        return initial;
+    }
+
+    list_element_t accumulator = initial;
+
+    for (size_t i = 0; i < list->length; ++i) {
+        accumulator = foldl(accumulator, list->elements[i]);
+    }
+
+    return accumulator;
+}
+
+list_t *reverse_list(list_t *list) {
+    if (!list) {
+        return NULL;
+    }
+
+    list_t *reversed_list = new_list(list->length, NULL);
+
+    if (!reversed_list) {
+        return NULL;
+    }
+
+    for (size_t i = list->length; i > 0; --i) {
+        reversed_list->elements[list->length - i] = list->elements[i - 1];
+    }
+
+    return reversed_list;
+}
+
+void delete_list(list_t *list) {
+    if (list != NULL) {
+        free(list);
+    }
+}