tcp_client_test1.cpp

基于TCP的客户端和服务器端的套接字编程

// TCP_Client_Test1.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include  <stdlib.h>



/* client.c - code for example client program that uses TCP */
#ifndef unix
//#define WIN32
#include <windows.h>
#include <winsock.h>
#else
#define closesocket close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif
#include <stdio.h>
#include <string.h>

#include <fcntl.h> 
#include <sys\stat.h> 
#include <io.h> 




#pragma   comment(lib,"Winmm.lib")
#pragma   comment(lib,"wsock32.lib")


#define PROTOPORT       5193            /* default protocol port number */
extern  int     errno;
//服务器端IP地址，如果是本地的直接用char    localhost[] =  "localhost";      
 /* default host name  */
char    localhost[] =  "localhost";       /* default host name  */

/*------------------------------------------------------------------------
 * Program:   client
 *
 * Purpose:   allocate a socket, connect to a server, and print all output
 *
 * Syntax:    client [ host [port] ]
 *
 *               host  - name of a computer on which server is executing
 *               port  - protocol port number server is using
 *
 * Note:  Both arguments are optional.  If no host name is specified,
 *            the client uses "localhost"; if no protocol port is
 *            specified, the client uses the default given by PROTOPORT.
 *
 *------------------------------------------------------------------------ */
//int     argc;
//char    *argv[];
int  main(int argc,char *argv[])
//int main(argc,argv)
{
        struct  hostent  *ptrh;    /* pointer to a host table entry       */
        struct  protoent *ptrp;     /* pointer to a protocol table entry   */
        struct  sockaddr_in sad;  /* structure to hold an IP address     */
        int     sd;                         /* socket descriptor                   */
        int     port;                      /* protocol port number                */
        char  *host;                  /* pointer to host name                */
        int      n;                         /* number of characters read           */
        char  buf[1000];          /* buffer for data from the server     */
	//#ifdef WIN32
          WSADATA wsaData;
          WSAStartup(0x0101, &wsaData);
	//#endif

		  memset((char *)&sad,0,sizeof(sad)); /* clear sockaddr structure */
        sad.sin_family = AF_INET;              /* set family to Internet     */

        /* Check command-line argument for protocol port and extract    */
        /* port number if one is specified.  Otherwise, use the default */
        /* port value given by constant PROTOPORT                       */

        if (argc > 2) {                 /* if protocol port specified   */
                port = atoi(argv[2]);   /* convert to binary            */
        } else 
       {
                port = PROTOPORT;       /* use default port number      */
        }
        if (port > 0)                   /* test for legal value         */
                sad.sin_port = htons((u_short)port);
        else {                          /* print error message and exit */
                fprintf(stderr,"bad port number %s\n",argv[2]);
                exit(1);
        }
/* Check host argument and assign host name. */

        if (argc > 1) {
                host = argv[1];         /* if host argument specified   */
        } else {
                host = localhost;
        }

        /* Convert host name to equivalent IP address and copy to sad. */

        ptrh = gethostbyname(host);
        if ( ((char *)ptrh) == NULL ) {
                fprintf(stderr,"invalid host: %s\n", host);
                exit(1);
        }
        memcpy(&sad.sin_addr, ptrh->h_addr, ptrh->h_length);
/* Map TCP transport protocol name to protocol number. */
        if ( ((int)(ptrp = getprotobyname("tcp"))) == 0) {
                fprintf(stderr, "cannot map \"tcp\" to protocol number");
                exit(1);
        }

        /* Create a socket. */
        sd = socket(PF_INET, SOCK_STREAM, ptrp->p_proto);
        if (sd < 0) {
                fprintf(stderr, "socket creation failed\n");
                exit(1);
        }
        /* Connect the socket to the specified server. */
        if (connect(sd, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
                fprintf(stderr,"connect failed\n");
                exit(1);
        }
        /* Repeatedly read data from socket and write to user's screen. */

        n = recv(sd, buf, sizeof(buf), 0);
        while (n > 0) {
                write(1,buf,n);
                n = recv(sd, buf, sizeof(buf), 0);
        }

        /* Close the socket. */

        closesocket(sd);

        /* Terminate the client program gracefully. */

        exit(0);
		return 0;
}