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1 files changed, 6 insertions, 0 deletions

diff --git a/sales_data.hpp b/sales_data.hpp
index cce4469..31929af 100644
--- a/sales_data.hpp
+++ b/sales_data.hpp
@@ -2,9 +2,15 @@
 #define SALES_DATA_H
 #include <string>
 struct SalesData {
+	std::string isbn() const { return BookNo; }
+	SalesData &combine(const SalesData);
+	double avg_price() const;
 	std::string BookNo;
 	unsigned int UnitsSold = 0;
 	double Revenue = 0.0;
 };
 
+SalesData add(const SalesData&, const SalesData&);
+std::ostream &print(std::ostream&, const SalesData&);
+std::istream &read(std::istream&, SalesData&);
 #endif