C++ Socket UDP "Hello World!"

//////////////////////////////////////////////////////////////////////////

// UDPServer.cpp



#include <stdio.h>

#include <WINSOCK2.H>



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

#define BUF_SIZE	64



int main(void)

{

	WSADATA	wsd;

	SOCKET	s;

	int		nRet;



	//          

	if(WSAStartup(MAKEWORD(2,2),&wsd) != 0)

	{

		printf("WSAStartup failed !
");

		return 1;

	}



	//      

	s = socket(AF_INET,SOCK_DGRAM,0);

	if(s == INVALID_SOCKET)

	{

		printf("socket() failed ,Error Code:%d
",WSAGetLastError());

		WSACleanup();

		return 1;

	}



	SOCKET		socketSrv = socket(AF_INET,SOCK_DGRAM,0);

	SOCKADDR_IN addrSrv;

	SOCKADDR_IN addrClient;

	char		buf[BUF_SIZE];

	int			len = sizeof(SOCKADDR);



	//        

	ZeroMemory(buf,BUF_SIZE);

	addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY);

	addrSrv.sin_family = AF_INET;

	addrSrv.sin_port = htons(5000);



	//      

	nRet = bind(socketSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));

	if(SOCKET_ERROR == nRet)   

    {   

        printf("bind failed !
");   

        closesocket(s);   

        WSACleanup();   

        return -1;   

    }



	//         

	nRet = recvfrom(socketSrv,buf,BUF_SIZE,0,(SOCKADDR*)&addrClient,&len);

	if(SOCKET_ERROR == nRet)   

    {   

        printf("recvfrom failed !
");   

        closesocket(s);   

        WSACleanup();   

        return -1;   

    }

	//              

	printf("Recv From Client:%s
",buf);



	//         

	sendto(socketSrv,"UDP Hello World !",sizeof("UDP Hello World !"),0,(SOCKADDR*)&addrClient,len);

	closesocket(s);

	WSACleanup();

	return 0;

}

//////////////////////////////////////////////////////////////////////////

// UDPClient.cpp



#include <stdio.h>

#include <WINSOCK2.H>



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

#define BUF_SIZE	64



int main(void)

{

	WSADATA	wsd;	

	SOCKET	s;



	//          

	if(WSAStartup(MAKEWORD(2,2),&wsd) != 0)

	{

		printf("WSAStartup failed !
");

		return 1;

	}



	//      

	s = socket(AF_INET,SOCK_DGRAM,0);

	if(s == INVALID_SOCKET)

	{

		printf("socket() failed, Error Code:%d
",WSAGetLastError());

		WSACleanup();

		return 1;

	}



	char		buf[BUF_SIZE];	//     

	SOCKADDR_IN	servAddr;		//         

	SOCKET		sockClient = socket(AF_INET,SOCK_DGRAM,0);

	int			nRet;



	ZeroMemory(buf,BUF_SIZE);

	strcpy(buf,"UDP Hello World !");



	//        

	servAddr.sin_family = AF_INET;

	servAddr.sin_addr.S_un.S_addr = inet_addr("192.168.1.254");

	servAddr.sin_port = htons(5000);



	//         

	int nServAddLen = sizeof(servAddr);

	if(sendto(sockClient,buf,BUF_SIZE,0,(sockaddr *)&servAddr,nServAddLen) == SOCKET_ERROR)

	{

		printf("recvfrom() failed:%d
",WSAGetLastError());

		closesocket(s);

		WSACleanup();

		return 1;

	}

	nRet = recvfrom(sockClient,buf,BUF_SIZE,0,(sockaddr *)&servAddr,&nServAddLen);

	if(SOCKET_ERROR == nRet)   

    {   

        printf("recvfrom failed !
");   

        closesocket(s);   

        WSACleanup();   

        return -1;   

    }



	//              

	printf("Recv From Server:%s
",buf);

	closesocket(s);

	WSACleanup();

	return 0;

}