C#嵌套switch语句

using System;

namespace DecisionMaking {

   class Program {

      static voID Main(string[] args) {
         int a = 100;
         int b = 200;

         switch (a) {
            case 100: 
            Console.Writeline("This is part of outer switch ");

            switch (b) {
               case 200:
               Console.Writeline("This is part of inner switch ");
               break;
            }
            break;
         }
         Console.Writeline("Exact value of a is : {0}", a);
         Console.Writeline("Exact value of b is : {0}", b);
         Console.Readline();
      }
   }
}