diff --git a/histogram.h b/histogram.h
new file mode 100644
index 0000000..8e69be4
--- /dev/null
+++ b/histogram.h
@@ -0,0 +1,7 @@
+#ifndef HISTOGRAM_H_INCLUDED
+#define HISTOGRAM_H_INCLUDED
+#include <vector>
+
+std::vector<size_t> make_histogram(const std::vector<double> &numbers, size_t bin_count);
+
+#endif // HISTOGRAM_H_INCLUDED