YieldExample2.cs

gistfile1.txt

using System;
using System.Collections.Generic;

namespace Yield
{
    class Program
    {
        //This is not real code only an example
        static void Main(string[] args)
        {
            // Apply Interest to all customer accounts
            foreach (Customer c in GetCustomers("Scotland"))
            {
                c.Balance = c.Balance * 1.01;
                repo.Update(c);
            }

        }

        private static IEnumerable<Customer> GetCustomers(string area)
        {
            //repo get Customer Numbers
            List<int> acctNos = repo.Get(area);

            foreach(var acc in acctNos)
            {
                //This is expensive
                Customer customer = repo.GetCustomer(acc);
                yield return customer;
            }
           
        }

    }

    public class Customer
    {
        public int AcctNumber { get; set; }
        public double Balance { get; set; }
    }
}