Add strategy pattern basic example

src/StrategyPattern/ShippingCalculator/ShippingMotivatingExample.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace StrategyPattern.ShippingCalculator
+{
+    public class ShippingMotivatingExample
+    {
+        public static void Run()
+        {
+            MShippingCalculator shippingCostCaluclator = new MShippingCalculator();
+            var indiaPrice = shippingCostCaluclator.GetPrice(new MOrder(), MShippingService.IndiaPost);
+            var postaPrice = shippingCostCaluclator.GetPrice(new MOrder(), MShippingService.Posta);
+            var tcePrice = shippingCostCaluclator.GetPrice(new MOrder(), MShippingService.TCE);
+
+            Console.WriteLine("The shipping cost for india is:{0}, for posta is {1} for tce is {2}", indiaPrice, postaPrice, tcePrice);
+        }
+    }
+
+    public class MShippingCalculator
+    {
+        public double GetPrice(MOrder order, MShippingService shippingService)
+        {
+            switch (shippingService)
+            {
+                case MShippingService.Posta:
+                    return ComputeForPosta(order, shippingService);
+                case MShippingService.TCE:
+                    return ComputeForTCE(order, shippingService);
+                case MShippingService.IndiaPost:
+                    return ComputeForIndiaPost(order, shippingService);
+                default:
+                    throw new Exception("Me not know the shipping service, boom boom");
+            }
+        }
+
+        private double ComputeForIndiaPost(MOrder order, MShippingService shippingService)
+        {
+            return 0.25;
+        }
+
+        private double ComputeForTCE(MOrder order, MShippingService shippingService)
+        {
+            return 1;
+        }
+
+        private double ComputeForPosta(MOrder order, MShippingService shippingService)
+        {
+            return 2;
+        }
+    }
+
+    public class MOrder
+    {
+
+    }
+
+    public enum MShippingService
+    {
+        Posta,
+        TCE,
+        IndiaPost
+    }
+}

src/StrategyPattern/ShippingCalculator/ShippingWithStrategyExample.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace StrategyPattern.ShippingCalculator
+{
+    public class ShippingWithStrategyExample
+    {
+        public static void Run()
+        {
+            ShippingCalculator shippingCostCaluclator = new ShippingCalculator();
+            var indiaPrice = shippingCostCaluclator.GetPrice(new Order(), new IndiaPost());
+            var postaPrice = shippingCostCaluclator.GetPrice(new Order(), new Posta());
+            var tcePrice = shippingCostCaluclator.GetPrice(new Order(), new TCE());
+
+            Console.WriteLine("The shipping cost for india is:{0}, for posta is {1} for tce is {2}", indiaPrice, postaPrice, tcePrice);
+        }
+    }
+
+    public class ShippingCalculator
+    {
+        public double GetPrice(Order order, ShippingService shippingService)
+        {
+            return shippingService.GetPrice(order);
+        }
+    }
+
+    public abstract class ShippingService
+    {
+        public abstract double GetPrice(Order o);
+    }
+
+    public class IndiaPost : ShippingService
+    {
+        public override double GetPrice(Order o)
+        {
+            return 0.25;
+        }
+    }
+
+    public class Posta : ShippingService
+    {
+        public override double GetPrice(Order o)
+        {
+            return 2;
+        }
+    }
+
+    public class TCE : ShippingService
+    {
+        public override double GetPrice(Order o)
+        {
+            return 1;
+        }
+    }
+
+    public class Order
+    {
+    }
+}