diff --git a/ch01/set1/set.h b/ch01/set1/set.h
index e69de29..8cb78ca 100644
--- a/ch01/set1/set.h
+++ b/ch01/set1/set.h
@@ -0,0 +1,11 @@
+#ifndef SET_H
+#define SET_H
+
+extern const void *set;
+
+void *add(void *set, const void *element);
+void *find(const void *set, const void *element);
+void *drop(void *set, const void *element);
+int contants(const void *set, const void *element);
+
+#endif
diff --git a/ch01/set1/new.h b/ch01/set1/new.h
index e69de29..c5fce81 100644
--- a/ch01/set1/new.h
+++ b/ch01/set1/new.h
@@ -0,0 +1,7 @@
+#ifndef NEW_H
+#define NEW_H
+
+void *new(cosnt void *type, ...);
+void delete(void *item);
+
+#endif
diff --git a/ch01/set1/object.h b/ch01/set1/object.h
index e69de29..d619491 100644
--- a/ch01/set1/object.h
+++ b/ch01/set1/object.h
@@ -0,0 +1,7 @@
+#ifndef OBJECT_H
+#define OBJECT_H
+
+extern const void *Object;
+int differ(const void *a, const void *b);
+
+#endif
This is a sample set