==========================================示例一
结论：
1，栈中的内存块按4的倍数进行分配（不是按照类型的大小分配的）
2，指针类型强制转换，得到的内容将无意义
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication2
{
class Program
{
static unsafe void Main(string[] args)
{
//1，栈中的内存块按4的倍数进行分配（不是按照类型的大小分配的）
//2，指针类型强制转换，得到的内容将无意义
int x = 10;
short y = -1;
byte y2 = 4;
double z = 10.1;
int* pX;
short* pY;
double* pZ;
pX = &x;
pY = &y;
pZ = &z;
//6B7E738 4 10
Console.WriteLin("address of x is {0:X},size is {1},value is {2}", (uint)&x, sizeof(int), x);
//6B7E734 2 -1
Console.WriteLine("address of y is {0:X},size is {1},value is {2}", (uint)&y, sizeof(short), y);
//6B7E730 1 4
Console.WriteLine("address of y2 is {0:X},size is {1},value is {2}", (uint)&y2, sizeof(byte), y2);
//6B7E728 8 10.1
Console.WriteLine("address of z is {0:X},size is {1},value is {2}", (uint)&z, sizeof(double), z);
//6B7E724 4 6B7E738 （取的指针的地址）
Console.WriteLine("address of pX is {0:X},size is {1},value is {2:X}", (uint)&pX, sizeof(int*), (uint)pX);
//6B7E720 4 6B7E734 （取的指针的地址）
Console.WriteLine("address of pY is {0:X},size is {1},value is {2:X}", (uint)&pY, sizeof(short*), (uint)pY);
//6B7E71C 4 6B7E728 （取的指针的地址）
Console.WriteLine("address of pZ is {0:X},size is {1},value is {2:X}", (uint)&pZ, sizeof(double*), (uint)pZ);
//改变了x的值
*pX = 20; //x=20,*pX=20
//指针强制装换，得到的值将无意义
pZ = (double*)pX;//*pZ的内容无意义
Console.ReadKey();
}
}
}
==========================================示例二
结论：
1，使用算法，改变指针
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static unsafe void Main(string[] args)
{
CurrencyStruce amount1, amount2;
CurrencyStruce* pAmount = &amount1;
long* pDollars = &(pAmount->Dollars);
byte* pCents = &((*pAmount).cents);
//642ED1C 16
Console.WriteLine("address of amount1 is {0:X},size is {1}", (uint)&amount1, sizeof(CurrencyStruce));
//642ED0C 16
Console.WriteLine("address of amount2 is {0:X},size is {1}", (uint)&amount2, sizeof(CurrencyStruce));
//642ED08 4 642ED1C
Console.WriteLine("address of pAmount is {0:X},size is {1},value is {2:X}", (uint)&pAmount, sizeof(CurrencyStruce*), (uint)pAmount);
//642ED04 4 642ED1C
Console.WriteLine("address of pDollars is {0:X},size is {1},value is {2:X}", (uint)&pDollars, sizeof(CurrencyStruce*), (uint)pDollars);
//642ED00 4 642ED24
Console.WriteLine("address of pCents is {0:X},size is {1},value is {2:X}", (uint)&pCents, sizeof(CurrencyStruce*), (uint)pCents);
*pDollars = 20;
//$20.0 $0.0
Console.WriteLine("amount1 is {0},amount2 is {1}", amount1, amount2);
//=================pAmount指针递减之后，其地址指向amount2（因为amount2栈中的地址在amount1的下面）
pAmount--;
//642ED08 4 642ED0C
Console.WriteLine("address of pAmount is {0:X},size is {1},value is {2:X}", (uint)&pAmount, sizeof(CurrencyStruce*), (uint)pAmount);
//=================pCents目前指向amount1.cents,使其指向amount2.cents
CurrencyStruce* pTempCurrency = (CurrencyStruce*)pCents;//pTempCurrency指针指向642ED24
pCents = (byte*)(--pTempCurrency);//pTempCurrency-1（因为CurrencyStruce占用16个字节）所以结果指向642ED14
*pCents = 3;
//$20.0 $0.3
Console.WriteLine("amount1 is {0},amount2 is {1}", amount1, amount2);
//=================查看类成员指针
CurrentClass c = new CurrentClass();
fixed (long* pCDollars = &(c.Dollars))
fixed (byte* pCCents = &(c.cents))
{
Console.WriteLine("address of c.Dollars is {0:X}",(uint)pCDollars);
Console.WriteLine("address of c.cents is {0:X}", (uint)pCCents);
*pCCents = 9;
Console.WriteLine(c);//输出：$0.9
}
Console.ReadKey();
}
}
//结构
struct CurrencyStruce
{
public long Dollars;
public byte cents;
public override string ToString()
{
return "$" + Dollars + "." + cents;
}
}
//类
class CurrentClass
{
public long Dollars;
public byte cents;
public override string ToString()
{
return "$" + Dollars + "." + cents;
}
}
}本文出自 “程序猿的家--Hunter” 博客，请务必保留此出处http://962410314.blog.51cto.com/7563109/1567953
原文地址：http://962410314.blog.51cto.com/7563109/1567953
