diff --git a/map.cc b/map.cc
index 8dbc7e6..cb1a3ef 100644
--- a/map.cc
+++ b/map.cc
@@ -47,6 +47,13 @@ tile::tile_in_dir(int dir_x, int dir_y)
 }
 
 
+void
+map::on_tick(void)
+{
+	for (int i = 0; i < w * h; i++)
+		tiles[i]->on_tick();
+}
+
 void
 map::print_map(void)
 {
diff --git a/map.h b/map.h
index a4fcc00..821cefc 100644
--- a/map.h
+++ b/map.h
@@ -55,11 +55,7 @@ public:
 		return *tiles[y * w + x];
 	};
 
-	void on_tick(void)
-	{
-		for (int i = 0; i < w * h; i++)
-			tiles[i]->on_tick();
-	}
+	void on_tick(void);
 
 	void print_map(void);
 };