//设置一个socket地址结构server_addr,代表服务器的internet地址, 端口
struct sockaddr_in server_addr;
bzero(&server_addr,sizeof(server_addr));
server_addr.sin_family = AF_INET;
if(inet_aton(argv[1],&server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数
{
printf("Server IP Address Error!\n");
exit(1);
}
server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
socklen_t server_addr_length = sizeof(server_addr);
//向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接
if(connect(client_socket,(struct sockaddr*)&server_addr, server_addr_length) < 0)
{
printf("Can Not Connect To %s!\n",argv[1]);
exit(1);
}

char buffer[BUFFER_SIZE];
bzero(buffer,BUFFER_SIZE);

//从服务器接收数据到buffer中
int length = recv(client_socket,buffer,BUFFER_SIZE,0);

if(length < 0)
{
printf("Recieve Data From Server %s Failed!\n", argv[1]);
exit(1);
}

printf("\n%s\n",buffer);

bzero(buffer,BUFFER_SIZE);

bzero(buffer,BUFFER_SIZE);
strcpy(buffer,"Hello, World! From Client\n");
//向服务器发送buffer中的数据
send(client_socket,buffer,BUFFER_SIZE,0);

if((stream = fopen("data","w+t"))==NULL)
{
printf("The file 'data' was not opened! \n");
}

else
bzero(buffer,BUFFER_SIZE);
length = 0;
while( length = recv(client_socket,buffer,BUFFER_SIZE,0))
{
if(length < 0)
{
printf("Recieve Data From Server %s Failed!\n", argv[1]);
break;
}

int write_length = fwrite(buffer,sizeof(char),length,stream);
if (write_length{
printf("File is Write Failed\n");
break;
}
bzero(buffer,BUFFER_SIZE);
}
printf("Recieve File From Server[%s] Finished\n", argv[1]);

//关闭 文件
fclose(stream);

//关闭socket
close(client_socket);
return 0;
}