VC++ UDP网络控制台程序

       采用的是VC2008,控制台应用程序，使用UDP编写。

1、服务端代码

//UDPServer.cpp

#include <WinSock2.h>
#include <stdio.h>

#define SERVERPORT 6000	//服务端口号

#pragma comment(lib, "WS2_32.lib");

int main(int argc, char *argv[])
{
	//加载套接字库
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;

	wVersionRequested = MAKEWORD( 2, 2 );
	
	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 ) {
		/* Tell the user that we could not find a usable */
		/* WinSock DLL.                                  */
		return -1;
	}

	/* Confirm that the WinSock DLL supports 2.2.*/
	/* Note that if the DLL supports versions greater    */
	/* than 2.2 in addition to 2.2, it will still return */
	/* 2.2 in wVersion since that is the version we      */
	/* requested.                                        */

	if ( LOBYTE( wsaData.wVersion ) != 2 ||
		HIBYTE( wsaData.wVersion ) != 2 ) {
			/* Tell the user that we could not find a usable */
			/* WinSock DLL.                                  */
			WSACleanup( );
			return -1; 
	}

	/* The WinSock DLL is acceptable. Proceed. */
	//创建套接字
	SOCKET sockServer = socket(AF_INET, SOCK_DGRAM, 0);
	if (INVALID_SOCKET == sockServer)
	{
		printf("socket() called failed! The error code is: %d\n", WSAGetLastError());
		return -1;
	}
	else
	{
		printf("socket() called succesful!\n");
	}
	
	//服务器端
	SOCKADDR_IN addrServer;
	addrServer.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	addrServer.sin_family = AF_INET;
	addrServer.sin_port = htons(SERVERPORT);

	//绑定套接字
	err = bind(sockServer, (SOCKADDR*)&addrServer, sizeof(SOCKADDR));
	if (SOCKET_ERROR == err)
	{
		printf("bind() called failed! The error code is: %d\n", WSAGetLastError());
		return -1;
	}
	else
	{
		printf("bind() called successful!\n");
	}

	//等待并接收数据
	SOCKADDR_IN addrClient;//用于接收发送端的地址信息
	int len = sizeof(SOCKADDR);
	char recvBuf[100];
	recvfrom(sockServer, recvBuf, 100, 0, (SOCKADDR*)&addrClient, &len);
	//打印接收到的数据
	printf("receive data:%s from client [%s,%d]", recvBuf, inet_ntoa(addrClient.sin_addr), addrClient.sin_port);
	
	//关闭套接字
	closesocket(sockServer);
	
	//终止套接字库的使用
	WSACleanup();
	
	return 0;
}

2、客户端代码

//UDPClient.cpp

#include <WinSock2.h>
#include <stdio.h>

#define SERVERPORT 6000	//服务端口号

#pragma comment(lib, "WS2_32.lib");

int main(int argc, char *argv[])
{
	//加载套接字库
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;

	wVersionRequested = MAKEWORD( 2, 2 );

	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 ) {
		/* Tell the user that we could not find a usable */
		/* WinSock DLL.                                  */
		return -1;
	}

	/* Confirm that the WinSock DLL supports 2.2.*/
	/* Note that if the DLL supports versions greater    */
	/* than 2.2 in addition to 2.2, it will still return */
	/* 2.2 in wVersion since that is the version we      */
	/* requested.                                        */

	if ( LOBYTE( wsaData.wVersion ) != 2 ||
		HIBYTE( wsaData.wVersion ) != 2 ) {
			/* Tell the user that we could not find a usable */
			/* WinSock DLL.                                  */
			WSACleanup( );
			return -1; 
	}
	
	//创建套接字
	SOCKET sockClient = socket(AF_INET, SOCK_DGRAM, 0);
	if (INVALID_SOCKET == sockClient)
	{
		printf("socket() called failed! The error code is: %d\n", WSAGetLastError());
		return -1;
	}
	else
	{
		printf("socket() called succesful!\n");
	}

	SOCKADDR_IN addrServer;
	addrServer.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	addrServer.sin_family = AF_INET;
	addrServer.sin_port = htons(SERVERPORT);
	
	//发送数据
	err = sendto(sockClient, "Hello", strlen("Hello")+1, 0, (SOCKADDR*)&addrServer, sizeof(SOCKADDR));
	if (SOCKET_ERROR == err)
	{
		printf("sendto() called failed! The error code is: %s\n", WSAGetLastError());
		return -1;
	}
	else
	{
		printf("sendto() called successful!\n");
	}

	//关闭套接字
	closesocket(sockClient);

	//终止套接字库的使用
	WSACleanup();

	return 0;
}

先启动服务端UDPServer程序，再启动客户端UDPClient程序，运行结果如下：

服务端UDPServer

客户端UDPClient

此时服务端UDPServer的结果会发生变化，会受到客户端发送过来的数据，如下图所示：

参考资料：

1、《VC++深入详解》 第14章网络编程 ，孙鑫主编

2、MSDN帮助文档