diff --git a/cv4/list_ops.c b/cv4/list_ops.c
index ee3c710..5589de1 100644
--- a/cv4/list_ops.c
+++ b/cv4/list_ops.c
@@ -1,48 +1,166 @@
-#ifndef LIST_OPS_H
-#define LIST_OPS_H
-
-#include <stdlib.h>
-#include <stdbool.h>
-#include <stdarg.h>
 #include "list_ops.h"
-#include "test-framework/unity.h"
 
-typedef int list_element_t;
+// Constructs a new list
+list_t *new_list(size_t length, list_element_t elements[]) {
+    list_t *list = malloc(sizeof(list_t) + length * sizeof(list_element_t));
+    if (list) {
+        list->length = length;
+        if (elements) {
+            for (size_t i = 0; i < length; i++) {
+                list->elements[i] = elements[i];
+            }
+        }
+    }
+    return list;
+}
 
-typedef struct {
-   size_t length;
-   list_element_t elements[];
-} list_t;
+// Appends entries to a list and returns the new list
+list_t *append_list(list_t *list1, list_t *list2) {
+    size_t length1 = list1->length;
+    size_t length2 = list2->length;
+    size_t new_length = length1 + length2;
+    list_t *new_list = malloc(sizeof(list_t) + new_length * sizeof(list_element_t));
+    if (new_list) {
+        new_list->length = new_length;
+        for (size_t i = 0; i < length1; i++) {
+            new_list->elements[i] = list1->elements[i];
+        }
+        for (size_t i = 0; i < length2; i++) {
+            new_list->elements[length1 + i] = list2->elements[i];
+        }
+    }
+    return new_list;
+}
 
-// constructs a new list
-list_t *new_list(size_t length, list_element_t elements[]);
+// Filters list returning only values that satisfy the filter function
+list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
+    size_t length = list->length;
+    size_t new_length = 0;
+    // Count the number of elements that satisfy the filter
+    for (size_t i = 0; i < length; i++) {
+        if (filter(list->elements[i])) {
+            new_length++;
+        }
+    }
+    // Create a new list with filtered elements
+    list_t *new_list = malloc(sizeof(list_t) + new_length * sizeof(list_element_t));
+    if (new_list) {
+        new_list->length = new_length;
+        size_t j = 0;
+        for (size_t i = 0; i < length; i++) {
+            if (filter(list->elements[i])) {
+                new_list->elements[j++] = list->elements[i];
+            }
+        }
+    }
+    return new_list;
+}
 
-// append entries to a list and return the new list
-list_t *append_list(list_t *list1, list_t *list2);
+// Returns the length of the list
+size_t length_list(list_t *list) {
+    return list->length;
+}
 
-// filter list returning only values that satisfy the filter function
-list_t *filter_list(list_t *list, bool (*filter)(list_element_t));
+// Returns a list of elements whose values equal the list value transformed by the mapping function
+list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
+    size_t length = list->length;
+    list_t *new_list = malloc(sizeof(list_t) + length * sizeof(list_element_t));
+    if (new_list) {
+        new_list->length = length;
+        for (size_t i = 0; i < length; i++) {
+            new_list->elements[i] = map(list->elements[i]);
+        }
+    }
+    return new_list;
+}
 
-// returns the length of the list
-size_t length_list(list_t *list);
-
-// return a list of elements whose values equal the list value transformed by
-// the mapping function
-list_t *map_list(list_t *list, list_element_t (*map)(list_element_t));
-
-// folds (reduces) the given list from the left with a function
+// Folds (reduces) the given list from the left with a function
 list_element_t foldl_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldl)(list_element_t,
-                                                  list_element_t));
+                          list_element_t (*foldl)(list_element_t, list_element_t)) {
+    size_t length = list->length;
+    list_element_t result = initial;
+    for (size_t i = 0; i < length; i++) {
+        result = foldl(result, list->elements[i]);
+    }
+    return result;
+}
 
-// folds (reduces) the given list from the right with a function
+// Folds (reduces) the given list from the right with a function
 list_element_t foldr_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldr)(list_element_t,
-                                                  list_element_t));
+                          list_element_t (*foldr)(list_element_t, list_element_t)) {
+    size_t length = list->length;
+    list_element_t result = initial;
+    for (size_t i = length; i > 0; i--) {
+        result = foldr(list->elements[i - 1], result);
+    }
+    return result;
+}
+
+// Reverse the elements of the list
+list_t *reverse_list(list_t *list) {
+    size_t length = list->length;
+    list_t *new_list = malloc(sizeof(list_t) + length * sizeof(list_element_t));
+    if (new_list) {
+        new_list->length = length;
+        for (size_t i = 0; i < length; i++) {
+            new_list->elements[i] = list->elements[length - i - 1];
+        }
+    }
+    return new_list;
+}
+
+// Destroy the entire list
+void delete_list(list_t *list) {
+    free(list);
+}
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-// reverse the elements of the list
-list_t *reverse_list(list_t *list);
 
-// destroy the entire list
-// list will be a dangling pointer after calling this method on it