September 2017 Update

Task/Scope-modifiers/C-sharp/scope-modifiers-1.cs

@@ -0,0 +1,13 @@
+public //visible to anything.
+protected //visible to current class and to derived classes.
+internal //visible to anything inside the same assembly (.dll/.exe).
+protected internal //visible to anything inside the same assembly and also to derived classes outside the assembly.
+private //visible only to the current class.
+
+//Modifier           | Class | Assembly | Subclass | World
+//--------------------------------------------------------
+//public             |  Y    |  Y       |  Y       |  Y
+//protected internal |  Y    |  Y       |  Y       |  N
+//protected          |  Y    |  N       |  Y       |  N
+//internal           |  Y    |  Y       |  N       |  N
+//private            |  Y    |  N       |  N       |  N

Task/Scope-modifiers/C-sharp/scope-modifiers-2.cs

@@ -0,0 +1,21 @@
+public interface IPrinter
+{
+    void Print();
+}
+
+public class IntPrinter : IPrinter
+{
+    void IPrinter.Print() { // explicit implementation
+        Console.WriteLine(123);
+    }
+
+    public static void Main() {
+        //====Error====
+        IntPrinter p = new IntPrinter();
+        p.Print();
+
+        //====Valid====
+        IPrinter p = new IntPrinter();
+        p.Print();
+    }
+}