diff --git a/src/main/c/GameTic_Tac_Toe/tictactoe.h b/src/main/c/GameTic_Tac_Toe/tictactoe.h
index 8b13789..46e2404 100644
--- a/src/main/c/GameTic_Tac_Toe/tictactoe.h
+++ b/src/main/c/GameTic_Tac_Toe/tictactoe.h
@@ -1 +1,3 @@
+#ifndef TICTACTOE_H
+#define TICTACTOE_H