diff --git a/text.h b/text.h
index 3ee5b0c..930d68a 100644
--- a/text.h
+++ b/text.h
@@ -1,6 +1,9 @@
 #ifndef TEXT_H_INCLUDED
 #define TEXT_H_INCLUDED
 
+#include <vector>
 
+std::vector<size_t>
+show_histogram_text(const std::vector<double>& bins);
 
 #endif // TEXT_H_INCLUDED