基于UDP的通讯

XX：那飘过的100~_~{2014/10/03 10:57}

UDP是一种面向非连接SOCK_DGRAM，提供无连接服务。数据包以独立包形式发送，不提供无措保证，数据能够丢失或反复。

UDP的Server和Client的差别相对照较模糊，仅仅要调用 sendto和 recvfrom 就能够给指定的地址收发数据。

1. server端：

// udpClient.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "tchar.h"

#pragma comment(lib,"wsock32.lib")
#include <stdio.h>
#include <winsock2.h>

BOOL InitWinsock();				//Winsock服务初始化

void main()
{

SOCKET socket1;
InitWinsock();
struct sockaddr_in local;
struct sockaddr_in from;
int err;
int fromlean=sizeof(from);

local.sin_family=AF_INET;
local.sin_port=htons(1234);					//监听端口
local.sin_addr.S_un.S_addr=INADDR_ANY;		//本机
socket1=socket(AF_INET,SOCK_DGRAM,0);

bind(socket1,(sockaddr *)&local,sizeof local);
while(true)
{
char buffer[1024]="\0";
printf("waiting for message from others \n");

err=recvfrom(socket1,buffer,sizeof(buffer),0,(sockaddr *)&from,&fromlean);
if(err!=SOCKET_ERROR)
{

printf("Received from %s--%s\n",inet_ntoa(from.sin_addr),buffer);
//给Client发信息
sendto(socket1,buffer,sizeof buffer,0,(sockaddr *)&from,fromlean);
}
Sleep(500);
}
closesocket(socket1);
}

BOOL InitWinsock()
{
int Error;
WORD Version;
WSADATA Wsa;
Version=MAKEWORD(2,2);
Error=WSAStartup(Version,&Wsa);

if(Error!=0)
{
return FALSE;
}
else
{
if(LOBYTE(Wsa.wVersion)!=2 || HIBYTE(Wsa.wHighVersion)!=2)
{
WSACleanup();
return FALSE;
}
}
return TRUE;
}

2.client

// udpClient.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "tchar.h"

#pragma comment(lib,"wsock32.lib")
#include <stdio.h>
#include <winsock2.h>

BOOL InitWinsock();				//Winsock服务初始化

void main()
{

SOCKET socket1;
InitWinsock();
struct sockaddr_in server;
int err;
int lean=sizeof(server);
server.sin_family=AF_INET;
server.sin_port=htons(1234);								//服务器的监听端口为1234
server.sin_addr.S_un.S_addr=inet_addr("192.168.1.18");		//设置为本机地址
socket1=socket(AF_INET,SOCK_DGRAM,0);
while(true)
{
char buffer[1024]="\0";
printf("input message \n");
scanf("%s",buffer);

if(strcmp(buffer,"bye")==0)
{
break;
}
err=sendto(socket1,buffer,sizeof(buffer),0,(sockaddr *)&server,lean);
if(err!=SOCKET_ERROR)
{

err=recvfrom(socket1,buffer,sizeof(buffer),0,(sockaddr *)&server,&lean);
if(err!=SOCKET_ERROR)
{

printf("receive from server:%s\n",buffer);
}
}
}
closesocket(socket1);
}

BOOL InitWinsock()
{
int Error;
WORD Version;
WSADATA Wsa;
Version=MAKEWORD(2,2);
Error=WSAStartup(Version,&Wsa);

if(Error!=0)
{
return FALSE;
}
else
{
if(LOBYTE(Wsa.wVersion)!=2 || HIBYTE(Wsa.wHighVersion)!=2)
{
WSACleanup();
return FALSE;
}
}
return TRUE;
}

启动client以及server端，查看执行效果：





程序仍然存在非常大的问题，慢慢改动咯！