Beginning C# 2008-from Novice-to-professional - A2Z Dotnet

34CHAPTER 2 ■ LEARNING ABOUT .NET NUMBER AND VALUE TYPESIn the bolded code, there is a reference to another namespace, type, and method witha pair of parentheses. This is called making a method call on a static class and static method.This says that the implementation of the method is the calling of another method.Notice how the other method is referenced using both namespace and type identifiers.This is how all types and methods are always referenced. A namespace identifier is only necessaryif the type (for example, class) is not defined in the current namespace.If you have namespaces with long names, this referencing can get tedious. As an alternative,you can add a using statement to reference the namespace, similar to the following.using MyMainTypes;namespace MyOtherMainTypes {static class AnotherType {public static void DoSomething() {AType.DoSomething();}}}The using statement says that if the code references any types that are not defined locally,look in this namespace (MyMainTypes in the example) to find the type. Note that if you use usingtwo namespaces that have identically named types, then referencing that type will result ina compiler failure, because it won’t know which type to reference.This covers the absolute basics of writing some code, and we are ready to write some codeto do something.Writing the Add() MethodWe’ll write the code to add two numbers. To begin, create a new project in Visual C#:1. Open Visual C# (if Visual C# is open, choose File ➤ Close Solution to ensure you havea clean slate).2. Click File ➤ New Project or choose Create: Project.3. Choose Class Library, name it Calculator, and click OK.4. Rename Class1.cs to Calculator.cs.5. Save the solution.We can now write the Add() method. Add the bolded code to the Calculator.cs file.using System;using System.Collections.Generic;using System.Text;namespace Calculator{public class Calculator{}