模拟Ethernet帧的发送

// Ethernet.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "Ethernet.h"
//#include "CSMA030390.h"
#include "cmath"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// The one and only application object
CWinThread *thread1,*thread2;//定义变量
DWORD ID1,ID2,Bus=0;//初始化共享内存
UINT aThread(LPVOID pParam);//线程A代表主机A
UINT bThread(LPVOID pParam);//线程B代表主机B
using namespace std;
CWinApp theApp;

using namespace std;

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
 int nRetCode = 0;

 // initialize MFC and print and error on failure
 if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
 {
  // TODO: change error code to suit your needs
  cerr << _T("Fatal Error: MFC initialization failed") << endl;
  nRetCode = 1;
 }
 else
 {
  // TODO: code your application's behavior here.
  //CString strHello;
  //strHello.LoadString(IDS_HELLO);
  //cout << (LPCTSTR)strHello << endl;
  thread1=AfxBeginThread(aThread,NULL);//启动线程A
  ID1=thread1->m_nThreadID;//线程A的ID号
  thread2=AfxBeginThread(bThread,NULL);
  ID2=thread2->m_nThreadID;
  getchar();
 }

 return nRetCode;
}

UINT aThread(LPVOID pParam)
{
 int i=0;
 int CollisionCounter=16;//冲突次数
 double collisionWindow=0.005;//冲突窗口取0.005
 int randNum=rand()%3;//随机数
Loop:if(Bus==0)
  {
   Bus=Bus|ID1;//或符号
   Sleep(12);
 
  if(Bus==ID1)
  {
   printf("%d Send Success/n/n",ID1);
   Bus=0;
   CollisionCounter=16;
   Sleep(rand()%10);
   i++;
   printf("主机A发送成功次数=%d/n/n",i);
   if(i<10)
    goto Loop;
  }
  else
  {
   printf("%d Send Collision/n/n",ID1);
   Bus=0;
   CollisionCounter--;
   if(CollisionCounter>0)
   {
    Sleep(randNum*(int)pow(2,(CollisionCounter>10)?10:CollisionCounter)*collisionWindow);
    goto Loop;
   }
   else
    printf("%ld send Failure/n/n",ID1);
  }
}
  goto Loop;
  return 0;
}

UINT bThread(LPVOID pParam)
{
 int j=0;
 int CollisionCounter=16;
 double collisionWindow=0.005;
 int randNum=rand()%3;
Loop:if(Bus==0)
  {
   Sleep(2);
   Bus=Bus|ID2;
   Sleep(3);
 
  if(Bus==ID2)
  {
   printf("%d Send Success/n/n",ID2);
   Bus=0;
   CollisionCounter=16;
   Sleep(rand()%10);
   j++;
   printf("主机B发送成功次数=%d/n/n",j);
   if(j<10)
    goto Loop;
  }
  else
  {
   printf("%d Send Collision/n/n",ID2);
   Bus=0;
   CollisionCounter--;
   if(CollisionCounter>0)
   {
    Sleep(randNum*(int)pow(2,(CollisionCounter>10)?10:CollisionCounter)*collisionWindow);
    goto Loop;
   }
   else
    printf("%ld send Failure/n/n",ID2);
  }
}
  goto Loop;
  return 0;
}