--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/number_utils.h	Tue Dec 12 23:52:50 2023 +0000
@@ -0,0 +1,17 @@
+/*
+ * This header file provides function prototype declarations
+ * for phone-number-related utility functions.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+uint16_t digits3_to_uint16(const char *numstr);
+uint16_t digits4_to_uint16(const char *numstr);
+
+bool is_nanp_valid_prefix(const char *numstr);
+
+int grok_number_string(const char *str, bool allow_hyphen);
+void dehyphen_number_string(const char *src, char *dest);