C#

return products.Sum(p => p.Price);

double total = 0.0;
foreach (Product p in products) total += p.Price;
return total;

using System.Collections.Generic;
namespace EssentialTools.Models {
 public class ShoppingCart {
 private LinqValueCalculator calc;
 public ShoppingCart(LinqValueCalculator calcParam) {
 calc = calcParam;
 }
 public IEnumerable<Product> Products { get; set; }
 public decimal CalculateProductTotal() {
 return calc.ValueProducts(Products);
 }
 }
}

//
public class SomeClass: IEnumerable
{
    private List<string> ListOStrings;


    public SomeClass()
    {
        ListOStrings = new List<string>
        {
          "one","two","three"      
        };
    }

    public IEnumerator GetEnumerator()
    {
        return ListOStrings.GetEnumerator();
    }
}

// now you can access the private List like this: in a method or EventHandler:

SomeClass someClass = new SomeClass();

foreach (var str in someClass)
{
    Console.WriteLine(str);
}