Add using a header and cpp file

CM2005 Object Oriented Programming/Topic 2/2.5.1/OrderBookEntry.cpp

@@ -0,0 +1,18 @@
+#include "OrderBookEntry.h"
+
+OrderBookEntry::OrderBookEntry
+(
+  double price,
+  double amount,
+  std::string timestamp,
+  std::string product,
+  OrderBookType orderType
+)
+:
+price{price},
+amount{amount},
+timestamp{timestamp},
+product{product},
+orderType{orderType}
+{
+}