1 files changed, 5 insertions, 0 deletions
diff --git a/sorters.h b/sorters.h
index 76c5443..dbaf59e 100644
--- a/sorters.h
+++ b/sorters.h
@@ -1,3 +1,6 @@
+#ifndef SORTERS_H
+#define SORTERS_H
+
 #include <stddef.h>
 
 void assert_sorted(int *buffer, size_t size);
@@ -17,3 +20,5 @@ extern const struct sorter {
 	const char *name;
 	sorterfn func;
 } sorters[];
+
+#endif