using System;  using System.Collections.Generic;  using System.Linq;  using System.Text;    namespace ConsoleApplication1  {      struct XYZ      {          public int a;          public int b;          public int c;          bool b1;          };        class Program      {          //静态变量存储在堆上，查看指针时需用fixed固定          static int m_sZ = 100;              //普通数据成员，也是放在堆上了，查看指针时需用fixed固定          int m_nData = http://www.mamicode.com/100;                       //等价于C/C++的 #define 语句，不分配内存          const int PI = 31415;            //unsafe可以放在Main函数声明中！！          static unsafe void Main(string[] args)          {              //简单的结构变量放在栈上，无需fixed              XYZ stData = http://www.mamicode.com/new XYZ();              stData.a = 100;              Console.WriteLine("结构变量= 0x{0:x}", (int)&stData);                  //数组变量的声明放在了栈上，数据放在了堆上，需用fixed固定              int[] arry = null;              arry = new int[10];              fixed(int *p = arry)              {                  Console.WriteLine("array = 0x{0:x}", (int)p);              }                //这些放在栈上的变量，可以直接使用指针指向              //从打印的指针的数据看，int是4字节的，double是8字节的              int y = 10;              int z = 100;              double f = 0.90;              Console.WriteLine("本地变量y = 0x{0:X}, z = 0x{1:X}", (int)&y, (int)&z);              Console.WriteLine("本地变量f = 0x{0:X}", (int)&f);                //下面失败              //fixed (int* p = &P.PI)              //{              //}                //放在堆里面的数据的地址，就必须用fixed语句！               string ss = "Helo";              fixed(char *p = ss)              {                  Console.WriteLine("字符串地址= 0x{0:x}", (int)p);                }                Program P = new Program();              //这个是类对象，放在堆里面              fixed(int *p = &P.m_nData)              {                  Console.WriteLine("普通类成员变量 = 0x{0:X}", (int)p);              }                //静态成员变量在堆上              fixed(int *p = &m_sZ)              {                  Console.WriteLine("静态成员变量 = 0x{0:X}", (int)p);              }                              //下面是每种类型的占用字节个数              Console.Write("\n\n下面是每种类型的占用字节个数\n");              Console.WriteLine("sizeof(void *) = {0}", sizeof(void*));              Console.WriteLine("sizeof(int) = {0}, * = {1}", sizeof(int), sizeof(int*));//4              Console.WriteLine("sizeof(long) = {0}, * = {1}", sizeof(long), sizeof(long*));//8              Console.WriteLine("sizeof(byte) = {0}, * = {1}", sizeof(byte), sizeof(byte*));//1              Console.WriteLine("sizeof(bool) = {0}, * = {1}", sizeof(bool), sizeof(bool*));//1              Console.WriteLine("sizeof(float) = {0}, * = {1}", sizeof(float), sizeof(float*));//4              Console.WriteLine("sizeof(double) = {0}, * = {1}", sizeof(double), sizeof(double*));//8              Console.WriteLine("sizeof(decimal) = {0}, * = {1}", sizeof(decimal), sizeof(decimal*));//16              Console.WriteLine("sizeof(char) = {0}, * = {1}", sizeof(char), sizeof(char*));//              Console.WriteLine("sizeof(XYZ) = {0}, * = {1}", sizeof(XYZ), sizeof(XYZ*));//              //Console.WriteLine("sizeof(object) = {0}, * = {1}", sizeof(object), sizeof(object*));//16              //Console.WriteLine("sizeof(C) = {0}, * = {1}", sizeof(C), sizeof(C*));//16            }      }  }  
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