diff --git a/modules/04_arrays_and_strings/src/c_arrays.cpp b/modules/04_arrays_and_strings/src/c_arrays.cpp
index 9290afb..38828aa 100644
--- a/modules/04_arrays_and_strings/src/c_arrays.cpp
+++ b/modules/04_arrays_and_strings/src/c_arrays.cpp
@@ -1,9 +1,37 @@
 #include "c_arrays.hpp"
 
+#include <climits>
+
 namespace arrays {
 
-auto array_sum(const int* data, std::size_t size) -> int { (void)data; (void)size; return 0; }
-auto array_max(const int* data, std::size_t size) -> int { (void)data; (void)size; return 0; }
-void reverse_array(int* data, std::size_t size) { (void)data; (void)size; }
+auto array_sum(const int* data, const std::size_t size) -> int {
+    auto sum = 0;
+    for (std::size_t i = 0; i < size; ++i) {
+        sum += data[i];
+    }
+    return sum;
+}
+
+
+auto array_max(const int* data, const std::size_t size) -> int {
+    auto max = INT_MIN;
+    for (std::size_t i = 0; i < size; ++i) {
+        if (data[i] > max) {
+            max = data[i];
+        }
+    }
+    return max;
+}
+
+void reverse_array(int* data, const std::size_t size) {
+    auto swap = [&data](const std::size_t i, const std::size_t j) {
+        const auto temp = data[i];
+        data[i] = data[j];
+        data[j] = temp;
+    };
+    for (std::size_t i = 0; i < size / 2; ++i) {
+        swap(i, size - i - 1);
+    }
+}
 
 }  // namespace arrays