added monte carlo method c#

CONTRIBUTORS.md

@@ -40,3 +40,4 @@ GuyPozner
 <br>
 William Boyles
 <br>
+sanstorik

chapters/monte_carlo/code/csharp/MonteCarlo.cs

@@ -0,0 +1,40 @@
+// submitted by vitalii shvetsov (@sanstorik)
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace MonteCarlo
+{
+    class MonteCarlo
+    {
+        private static Random random = new Random(47);
+        private int Radius { get; set; }
+        private int Samples { get; set; }
+
+
+        public MonteCarlo(int radius = 1, int samples = 1000000)
+        {
+            Radius = radius;
+            Samples = samples;
+        }
+
+
+        public double Run()
+        {
+            int piCount = 0;
+
+            for (int i = 0; i < Samples; i++)
+            {
+                var randomX = random.NextDouble() * Radius;
+                var randomY = random.NextDouble() * Radius;
+
+                if (IsInCircle(randomX, randomY)) piCount++;
+            }
+
+            return 4 * piCount / (double)Samples;
+        }
+
+
+        private bool IsInCircle(double x, double y) => x * x + y * y < Radius * Radius;
+    }
+}

chapters/monte_carlo/code/csharp/Program.cs

@@ -0,0 +1,18 @@
+using System;
+
+// submitted by vitalii shvetsov (@sanstorik)
+namespace MonteCarlo
+{
+    class Program
+    {
+        public static void Main(string[] args)
+        {
+            double piEstimate = new MonteCarlo(1, 1000000).Run();
+
+            Console.WriteLine("Pi estimate = {0}", piEstimate);
+            Console.WriteLine("Pi error = {0}", 100 * (Math.Abs(Math.PI - piEstimate)) / Math.PI);
+
+            Console.ReadLine();
+        }
+    }
+}

chapters/monte_carlo/monte_carlo.md

@@ -59,8 +59,11 @@ each point is tested to see whether it's in the circle or not:
 [import:13-15, lang:"java"](code/java/MonteCarlo.java)
 {% sample lang="swift" %}
 [import:21-25, lang:"swift"](code/swift/monte_carlo.swift)
+{% sample lang="csharp" %}
+[import:37-39, lang:"csharp"](code/csharp/MonteCarlo.cs)
 {% endmethod %}
 
+
 If it's in the circle, we increase an internal count by one, and in the end,
 
 $$
@@ -123,6 +126,8 @@ Feel free to submit your version via pull request, and thanks for reading!
 {% sample lang="swift" %}
 ### Swift
 [import, lang:"swift"](code/swift/monte_carlo.swift)
+### CSharp
+[import, lang:"csharp"](code/csharp/MonteCarlo.cs)
 {% endmethod %}