diff --git a/puissance4.c b/puissance4.c
index 78e3ce1e7fac8db72c2babda8f47201c116cd512..45b15bbf699295f7d65b2d74f3f3e65e02df7fde 100644
--- a/puissance4.c
+++ b/puissance4.c
@@ -24,7 +24,7 @@ bool validate_arguments(char const* argv[], int* game_mode, int* row_count, int*
 int main(int argc, char const* argv[]) {
     if (argc != 4) {
         print_usage(argv[0]);
-        return false;
+        return EXIT_FAILURE;
     }
 
     int game_mode, row_count, col_count;
diff --git a/src/board/board.c b/src/board/board.c
index 8abebe69ac6ddae43485755982eb7f9e5b9f5f07..18e751ecf50dce7f2fc6b5368f97ba0296606b3d 100644
--- a/src/board/board.c
+++ b/src/board/board.c
@@ -19,13 +19,10 @@ int destroy_board(int rows, int** board) {
 void print_board(int rows, int cols, int** board) {
     for (int row = -1; row <= rows; row++) {
         if (row == -1) {
-            // Top border of the board
             printf("\n┌");
         } else if (row == rows) {
-            // Bottom border of the board
             printf("└");
         } else {
-            // Print left vertical border
             printf("│");
         }
 
diff --git a/src/board/test_board.h b/src/board/test_board.h
index 4e2d839c5f5e0f33bf153df7605775af5818ce78..542c4d5aa23666a4ab976784aa14cab77b8c2df4 100644
--- a/src/board/test_board.h
+++ b/src/board/test_board.h
@@ -1,6 +1,11 @@
 #ifndef _TEST_BOARD_H_
 #define _TEST_BOARD_H_
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
 #include "board.h"
 #include "../test_puissance4.h"
 
diff --git a/src/computer/test_computer.h b/src/computer/test_computer.h
index 75997aa485762d752b4b0b66356dee8476b76a44..a56c48372575a7ccb39af3cd12fd5fc22f633aab 100644
--- a/src/computer/test_computer.h
+++ b/src/computer/test_computer.h
@@ -1,6 +1,11 @@
 #ifndef _TEST_COMPUTER_H_
 #define _TEST_COMPUTER_H_
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
 #include "computer.h"
 #include "../game/game.h"
 #include "../test_puissance4.h"
diff --git a/src/game/game.h b/src/game/game.h
index f550bf2cd21e65126bf763b084516e1983d8f627..efe0c76f391961c3f87621c60076771cb7654db0 100644
--- a/src/game/game.h
+++ b/src/game/game.h
@@ -1,5 +1,5 @@
-#ifndef _GAME_H
-#define _GAME_H
+#ifndef _GAME_H_
+#define _GAME_H_
 
 #include <stdbool.h>
 #include <stdio.h>
diff --git a/src/game/test_game.h b/src/game/test_game.h
index 2e775afa0fe48c8ec8528360dda706058ecc0c99..b2ba51c112facb1d96f63e2f87d6db7eaf216e36 100644
--- a/src/game/test_game.h
+++ b/src/game/test_game.h
@@ -1,6 +1,11 @@
 #ifndef _TEST_GAME_H_
 #define _TEST_GAME_H_
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
 #include "game.h"
 #include "../computer/computer.h"
 #include "../test_puissance4.h"