diff --git a/histogram.h b/histogram.h
new file mode 100644
index 0000000..9853bae
--- /dev/null
+++ b/histogram.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <vector>
+
+std::vector <size_t> make_histogram(const std:: vector <double>& numbers, size_t bin_count);