diff --git a/histogram.h b/histogram.h
index 07979b8..1eab698 100644
--- a/histogram.h
+++ b/histogram.h
@@ -2,3 +2,5 @@
 #include <vector>
 
 std::vector<size_t> make_histogram(const std::vector<double>& numbers, size_t bin_count);
+double compute_bin_size(const std::vector<double>& numbers, size_t bin_count);
+void show_histogram_svg(const std::vector<size_t>& bins, double bin_size, double min_val);