chap5_essential_language_features/essential_csharp_features/Program.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using automatically_implemented_properties;
 
 namespace automatically_implemented_properties
@@ -10,70 +9,35 @@ namespace automatically_implemented_properties
     {
         static void Main(string[] args)
         {
-            Product[] products =
+            // create and populate Shopping Cart
+            ShoppingCart cart = new ShoppingCart
             {
-                new Product {Name = "Kayak", Category = "Watersports", Price = 275M},
-                new Product {Name = "Lifejacket", Category = "Watersports", Price = 48.95M},
-                new Product {Name = "Soccer ball", Category = "Soccer", Price = 19.50M},
-                new Product {Name = "Corner flag", Category = "Soccer", Price = 34.95M}
-            };
-
-            var results = from product in products
-                orderby product.Price descending
-                select new
+                Products = new List<Product>
                 {
-                    product.Name,
-                    product.Price
-                };
-
-            int count = 0;
-            // print out the names
-            foreach (var p in results)
-            {
-                Console.WriteLine("Item: {0}, Cost: {1}", p.Name, p.Price);
-                if (++count == 3)
-                {
-                    break;
+                    new Product {Name = "Kayak", Price = 275M},
+                    new Product {Name = "Lifejacket", Price = 48.95M},
+                    new Product {Name = "Soccer ball", Price = 19.50M},
+                    new Product {Name = "Corner flag", Price = 34.95M}
                 }
-            }
+            };
+            // get total value of the products in cart
+            decimal cartTotal = cart.TotalPrices();
+            
+            Console.WriteLine("Total: {0:c}", cartTotal);
         }
 
     }
 
     public static class MyExtensionMethod
     {
-        public static decimal TotalPrices(this IEnumerable<Product> productEnum)
+        public static decimal TotalPrices(this ShoppingCart cartParam)
         {
             decimal total = 0;
-            foreach (Product prod in productEnum)
+            foreach (Product prod in cartParam.Products)
             {
                 total += prod.Price;
             }
             return total;
         }
-
-        public static IEnumerable<Product> FilterByCategory(this IEnumerable<Product> productEnum,
-                                                            string categoryParam)
-        {
-            foreach (Product prod in productEnum)
-            {
-                if (prod.Category == categoryParam)
-                {
-                    yield return prod;
-                }
-            }
-        }
-
-        public static IEnumerable<Product> Filter(this IEnumerable<Product> productEnum,
-            Func<Product, bool> selectorParam)
-        {
-            foreach (Product prod in productEnum)
-            {
-                if (selectorParam(prod))
-                {
-                    yield return prod;
-                }
-            }
-        }
     }
 }

chap5_essential_language_features/essential_csharp_features/ShoppingCart.cs

@@ -1,20 +1,9 @@
-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 
 namespace automatically_implemented_properties
 {
-    public class ShoppingCart : IEnumerable<Product>
+    public class ShoppingCart
     {
         public List<Product> Products { get; set; }
-
-        public IEnumerator<Product> GetEnumerator()
-        {
-            return Products.GetEnumerator();
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return GetEnumerator();
-        }
     }
 }