server4.cpp

此代码为udp通信程序

#include"Winsock.h"
#include"Windows.h"
#include"stdio.h"
//#include"stdafx.h"
#include"stdlib.h"
#pragma comment(lib,"wsock32.lib")
#define RECV_PORT 2000
#define SEND_PORT 3000

SOCKET sock;
DWORD StartSock()
{
   WSADATA WSAData;
   sockaddr_in ServerAddr;
   if(WSAStartup(MAKEWORD(2,2),&WSAData)!=0)  //初始化套接字
   {
	   printf("sock init fail!\n");
	   return(-1);
   }
   sock=socket(AF_INET,SOCK_DGRAM,0);
   if(sock==SOCKET_ERROR)
   {
	   printf("sock create fail!");
	   WSACleanup();
       return(-1);
   }
        ServerAddr.sin_family=AF_INET; //
	ServerAddr.sin_addr.s_addr=htonl(INADDR_ANY);
	ServerAddr.sin_port=htons(RECV_PORT);

	if(bind(sock,(struct sockaddr FAR *)&ServerAddr,sizeof(ServerAddr))==SOCKET_ERROR)
	{
		printf("sock bind error code!");
		closesocket(sock);
		WSACleanup();
		return(-1);
	}
   return(1);
}

DWORD UdpRecv()
{
	char RecvBuff[80];
	int RecvLength;
	int alen;
	int i;
	int length;
	sockaddr_in Client;
//	Client.sin_family=AF_INET; //填充发送方地址及端口号
//	Client.sin_addr.s_addr=inet_addr("59.74.24.138");
//	Client.sin_port=htons(SEND_PORT);
	alen=sizeof(Client);
	printf("Waiting for recv\n");
	for(;;)
	{
		memset(RecvBuff,0,80);
		RecvLength=recvfrom(sock,RecvBuff,80,0,(struct sockaddr *)&Client,&alen);
		if(RecvLength<=0)
		{
			printf("data receive fail");
			closesocket(sock);
			WSACleanup();
			return(-1);
		}
		else
		{
			if (strcmp(RecvBuff,"exit")==0)
				break;
			for(i=0;i<RecvLength;i++)
			
				printf("%c",RecvBuff[i]);
				//把收到的数据在返回去
				length=sendto(sock,RecvBuff,RecvLength,MSG_DONTROUTE,(struct sockaddr *)&Client,sizeof(Client));
                 printf("\n");
			}
		}
		return(1);
	}


void main()
{
	StartSock();
	UdpRecv();
}