using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class Customer
{
public string ID { get; set; }
public string City { get; set; }
public string Country { get; set; }
public string Region { get; set; }
public decimal Sales { get; set; }
}
class Order
{
public string ID { get; set; }
public decimal Amount { get; set; }
}
class Program
{
static void Main(string[] args)
{
List orders = new List {
new Order { ID="R", Amount=900 },
new Order { ID="S", Amount=1000 },
new Order { ID="T", Amount=1100 }
};
List customers = new List {
new Customer { ID="Q", City="London", Country="UK", Region="Europe", Sales=8000 },
new Customer { ID="R", City="Beijing", Country="China", Region="Asia", Sales=9000 },
new Customer { ID="T", City="Lima", Country="Peru", Region="South America", Sales=2002 }
};
var customerIDs = from c in customers select c.ID;
var orderIDs = from o in orders select o.ID;
var ordersNoCustomers = orderIDs.Except(customerIDs);
foreach (var item in ordersNoCustomers)
{
Console.Write("{0} ", item);
}
}
}