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1 files changed, 17 insertions, 1 deletions

diff --git a/sales_data.hpp b/sales_data.hpp
index 31929af..7cb3022 100644
--- a/sales_data.hpp
+++ b/sales_data.hpp
@@ -3,14 +3,30 @@
 #include <string>
 struct SalesData {
 	std::string isbn() const { return BookNo; }
-	SalesData &combine(const SalesData);
+	SalesData &combine(const SalesData&);
 	double avg_price() const;
 	std::string BookNo;
 	unsigned int UnitsSold = 0;
 	double Revenue = 0.0;
 };
 
+double SalesData::avg_price() const {
+
+	if (UnitsSold)
+		return Revenue / UnitsSold;
+	else
+		return 0;
+}
+
+SalesData& SalesData::combine(const SalesData &rhs) {
+
+	UnitsSold += rhs.UnitsSold;
+	Revenue += rhs.Revenue;
+	return *this;
+}
+
 SalesData add(const SalesData&, const SalesData&);
 std::ostream &print(std::ostream&, const SalesData&);
 std::istream &read(std::istream&, SalesData&);
+
 #endif