Add using a header and cpp file

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

@@ -0,0 +1,65 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <OrderBookEntry.h>
+
+double computeAveragePrice(std::vector<OrderBookEntry>& entries)
+{
+  double avg = 0;
+  for(unsigned int i=0; i<entries.size(); ++i) //thid doesn't create a copy, ++i increments on the same variable
+  {
+    //std::cout << "The price is " << entries[i].price << std::endl;
+    avg += entries[i].price;
+  }
+  return avg/entries.size();
+}
+
+int main()
+{
+
+  std::vector<OrderBookEntry> orders;
+
+  orders.push_back( OrderBookEntry{
+                                    10000,
+                                    0.002,
+                                    "2020/03/17 17:01:24.884492",
+                                    "BTC/USDT",
+                                    OrderBookType::bid});
+
+  orders.push_back( OrderBookEntry{
+                                    50000,
+                                    0.002,
+                                    "2020/03/17 17:01:24.884492",
+                                    "BTC/USDT",
+                                   OrderBookType::bid});
+
+  // Version 1
+  std::cout << "Version 1" << std::endl;
+  for(OrderBookEntry order : orders) //this create a copy of the members of orders and assigns it to 'order'
+  {
+    std::cout << "The price is " << order.price << std::endl;
+  }
+
+  std::cout << "---new line---" << std::endl;
+
+  for(OrderBookEntry &order : orders) //this doesn't crate a copy
+  {
+    std::cout << "The price is " << order.price << std::endl;
+  }
+
+  // Version 2
+  std::cout << "Version 2" << std::endl;
+  for(unsigned int i=0; i<orders.size(); ++i) //thid doesn't create a copy, ++i increments on the same variable
+  {
+    std::cout << "The price is " << orders[i].price << std::endl;
+  }
+
+  //version 3
+  std::cout << "Version 3" << std::endl;
+  for(unsigned int i=0; i<orders.size(); ++i) //thid doesn't create a copy, ++i increments on the same variable
+  {
+    std::cout << "The price is " << orders.at(i).price << std::endl;
+  }
+
+  std::cout << "Average price: " << computeAveragePrice(orders) << std::endl;
+}