Implement constructor to create object from its own instance

src/BuyOrder.java

@@ -3,4 +3,8 @@ public class BuyOrder extends Order {
 	BuyOrder(int time, Customer c, Stock stock, int qty, float price) {
 		super(time, "BUY", c, stock, qty, price);
 	}
+	
+	BuyOrder(BuyOrder b) {
+		super(b);
+	}
 }

src/SellOrder.java

@@ -2,4 +2,8 @@ public class SellOrder extends Order {
 	SellOrder(int time, Customer c, Stock stock, int qty, float price) {
 		super(time, "SELL", c, stock, qty, price);
 	}
+	
+	SellOrder(SellOrder s) {
+		super(s);
+	}
 }