diff --git a/CM2005 Object Oriented Programming/Topic 4/4.5.4/OrderBook.h b/CM2005 Object Oriented Programming/Topic 4/4.5.4/OrderBook.h
index e6421a5..82ca373 100644
--- a/CM2005 Object Oriented Programming/Topic 4/4.5.4/OrderBook.h	
+++ b/CM2005 Object Oriented Programming/Topic 4/4.5.4/OrderBook.h	
@@ -20,6 +20,7 @@ class OrderBook
       * If no next timestamp is found, wraps to the start */
     std::string getNextTime(std::string timestamp);
     void insertOrder(OrderBookEntry& order);
+    std::vector<OrderBookEntry> matchAsksToBids();
     static double getHighPrice(std::vector<OrderBookEntry>& orderList);
     static double getLowPrice(std::vector<OrderBookEntry>& orderList);
   private: