client.c

linux环境下的ＴＣＰ应用程序

#include        <stdio.h>
#include        <stdlib.h>
#include        <unistd.h>
#include        <errno.h>
#include        <string.h>
#include	<netdb.h>
#include        <sys/types.h>
#include        <sys/socket.h>
#include        <netinet/in.h>
#include        <arpa/inet.h>
   
                                                                                                               
#define MYPORT  3490
#define MAXDATASIZE       100



/*   

 用法：如：client 59.69.74.2
 
*/

                                                                                                               
int     main(int argc,char *argv[])
{
        int     sockfd,numbytes;
        struct  sockaddr_in     server_addr;
	struct	hostent	*server;
        char    buf[MAXDATASIZE];
	
	if(argc!=2)
	{
		fprintf(stderr,"usages:client hostname\n");
		exit(1);
	}
        if((server=gethostbyname(argv[1]))==NULL)
	{
		perror("gethostbyname");
		exit(1);
	}                                                                                                       
        if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
        {
                perror("socket");
                exit(1);
        }
         //绑定服务器的IP和PORT；                                                                                                      
        server_addr.sin_family=AF_INET;
        server_addr.sin_port=htons(MYPORT);
        server_addr.sin_addr=*((struct in_addr *)server->h_addr);
        //也可server_addr.sin_addr.s_addr=inet_addr(argv[1]);
	memset(&(server_addr.sin_zero),'\0',8);
	//也可bzero(&(server_addr.sin_zero),8);

	if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof(struct sockaddr))==-1)
	{
		perror("connect");
                exit(1);
	}

	if((numbytes=recv(sockfd,buf,MAXDATASIZE-1,0))==-1)
	{
                perror("recv");
                exit(1);
        }
        buf[numbytes]='\0';
	printf("Received:%s",buf);
        close(sockfd);
        return 0;
}