C#通过引用传递参数

using System;

namespace CalculatorApplication {

   class NumberManipulator {

      public void swap(ref int x, ref int y) {
         int temp;

         temp = x; /* save the value of x */
         x = y;    /* put y into x */
         y = temp; /* put temp into y */
      }

      static void Main(string[] args) {
         NumberManipulator n = new NumberManipulator();

         /* local variable definition */
         int a = 100;
         int b = 200;

         Console.WriteLine("Before swap, value of a : {0}", a);
         Console.WriteLine("Before swap, value of b : {0}", b);

         /* calling a function to swap the values */
         n.swap(ref a, ref b);

         Console.WriteLine("After swap, value of a : {0}", a);
         Console.WriteLine("After swap, value of b : {0}", b);

         Console.ReadLine();

      }
   }
}