diff --git a/three files/func.c b/three files/func.c
new file mode 100644
index 0000000000000000000000000000000000000000..9bfe28cd0b8291fd4404141b9b24c6590d325795
--- /dev/null
+++ b/three files/func.c	
@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include "func.h"
+
+int func_name_or_id(){
+#ifdef PRINT_ID
+	printf("201723267\n");
+	return 0;
+
+#else 
+	printf("LEESANGKYEONG\n");
+	return 1;
+#endif
+}
+
diff --git a/three files/func.h b/three files/func.h
new file mode 100644
index 0000000000000000000000000000000000000000..33718ed21723ffb1e38445656f4857bb2eda0d97
--- /dev/null
+++ b/three files/func.h	
@@ -0,0 +1 @@
+extern int func_name_or_id();
diff --git a/three files/main.c b/three files/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..8ec9279bd3b5fc5a7e3100f3b42ceab943127d9b
--- /dev/null
+++ b/three files/main.c	
@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include "func.h"
+
+
+int main(){
+
+	printf("%d\n", func_name_or_id());
+}
+