Add using a header and cpp file

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

@@ -0,0 +1,23 @@
+#include <string>
+
+enum class OrderBookType
+{
+  bid,
+  ask
+};
+
+class OrderBookEntry
+{
+  public:
+    OrderBookEntry(
+      double price,
+      double amount,
+      std::string timestamp,
+      std::string product,
+      OrderBookType orderType);
+    double price;
+    double amount;
+    std::string timestamp;
+    std::string product;
+    OrderBookType orderType;
+};