diff --git a/lec06/count1.c b/lec06/count1.c
index 948f9f651ff67febda764d17fa274f0f9784ccbe..03c18ce4327676835f850930817c252fbb43fcc4 100644
--- a/lec06/count1.c
+++ b/lec06/count1.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#define VALUE_ONE 1
 
 // Count number of 1 (binary)
 
diff --git a/lec06/test.c b/lec06/test.c
new file mode 100644
index 0000000000000000000000000000000000000000..235dbcbac624f2d61f5976f669bb64f6ba3bd888
--- /dev/null
+++ b/lec06/test.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+
+int main()
+{
+        int a = 100;
+        int b = 200;
+
+        fprintf(stdout, "%d : %d\n", a, &a); // &a는 a가 저장된 주소
+        fprintf(stdout, "%d : %d\n", b, &b);
+}