diff --git a/src/types.hpp b/src/types.hpp
index f6c8fa1..0d5210b 100644
--- a/src/types.hpp
+++ b/src/types.hpp
@@ -66,10 +66,10 @@ struct Entity {
 
   basic_cords Central_position(std::optional<float> x = std::nullopt,
                                std::optional<float> y = std::nullopt) {
-    if (x != NULL) {
+    if (x != std::nullopt) {
       position.x = *x - position.w / 2;
     }
-    if (y != NULL) {
+    if (y != std::nullopt) {
       position.y = *y - position.h / 2;
     }