윈속 : echo 클라이언트 프로그램

#include <stdio.h>
#include <winsock2.h>

#define PORT_NUM 3800
#define MAXLEN 1024

int main(int argc, char **argv)
{
	SOCKET sockfd;
	WSADATA wsaData;
	struct sockaddr_in addr;

	char buf[MAXLEN];
	char rbuf[MAXLEN];

	if(argc !=2)
	{
		printf("Usage : %s [ip address]\n", argv[0]);
		return 1;
	}

	if(WSAStartup(MAKEWORD(2,2), &wsaData) != NO_ERROR)
	{
		return 1;
	}

	if((sockfd = socket(AF_INET,SOCK_STREAM, 0)) == INVALID_SOCKET) 
	{
		return 1;
	}
	memset((void *)&addr, 0x00, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = inet_addr(argv[1]);
	addr.sin_port = htons(PORT_NUM);

	if(connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
	{
		return 1;
	}
	while(1)
	{
		 printf("> ");
		 fgets(buf, MAXLEN-1, stdin);
		 if(strncmp(buf, "quit\n",5) == 0)
	     {
			  break;
		 }

		 send(sockfd, (void *)buf, strlen(buf), 0);
		 memset(rbuf, 0x00, MAXLEN);
  		 recv(sockfd, (void *)buf, MAXLEN, 0);
		 printf("s -> %s\n", buf);
	}
	closesocket(sockfd);
	WSACleanup();
	return 0;
}