#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
    WSADATA wsaData;
    char *nodename;
    char *servname = "echo";
    ADDRINFO hints;
    LPADDRINFO ai, ai0;
    int e;
    SOCKET s;
    char linebuf[BUFSIZ];

    /** Process command line arguments (read the server name from the command line) */
    if (argc != 2) {
	fprintf(stderr, "syntax: tcp-echo-client servername\n");
	exit(1);
    }
    nodename = argv[1];

    /** Initialize WinSock */
    if (WSAStartup(MAKEWORD(2, 2), &wsaData)) {
	fprintf(stderr, "can not initilize WinSock\n");
	exit(1);
    }

    /** Perform name resolution and create ADDRINFO list */
    memset(&hints, 0, sizeof(hints));
    /* IPv6/IPv4 */
    hints.ai_family = AF_UNSPEC;
    /* Specify stream-type (TCP) socket */
    hints.ai_socktype = SOCK_STREAM;
    /* Perform name resolution and create ADDRINFO list.  ai0 is the first item of the list */
    if (e = getaddrinfo(nodename, servname, &hints, &ai0)) {
	fprintf(stderr, "%s\n", gai_strerror(e));
	exit(1);
    }

    /** Keep attempting to connect using each item in the ADDRINFO list */
    /** until it connects to the server successfully. */
    for (ai = ai0; ai; ai = ai->ai_next) {
	/* Attempt to create a socket.  If this fails, */
	/* attempt to connect using the next item in the ADDRINFO list. */
	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
	if (s == INVALID_SOCKET)
	    continue;

	/* Attempt to connect to the server.  If this fails, */
	/* attempt to connect using the next item in the ADDRINFO list. */
	if (connect(s, ai->ai_addr, ai->ai_addrlen) == SOCKET_ERROR) {
	    closesocket(s);
	    s = INVALID_SOCKET;
	    continue;
	}

	/* Since connection was successful, quit attempts to connect here. */
	printf("connected\n");
	break;
    }

    /** When attempts to connect using all of the ADDRINFO list items fail, */
    /** the value of s is INVALID_SOCKET. */
    if (s == INVALID_SOCKET) {
	freeaddrinfo(ai0);
	WSACleanup();
	fprintf(stderr, "can not connect server(%s)\n", nodename);
	exit(1);
    }

    /** Process I/O between the client and the server. */
    /** Send the character string to the server and receive a response from the server. */
    while (fgets(linebuf, sizeof(linebuf), stdin) != NULL) {

	/* Send the character string received from the standard input to the server. */
	if (send(s, linebuf, strlen(linebuf), 0) == SOCKET_ERROR) {
	    fprintf(stderr, "send error\n");
	    exit(1);
	}

	/* Display the character string returned by the server. */
	if (recv(s, linebuf, sizeof(linebuf), 0) == SOCKET_ERROR) {
	    fprintf(stderr, "recv error\n");
	    exit(1);
	}
	printf(linebuf);

    }

    freeaddrinfo(ai0);
    WSACleanup();
}