9. 退出FTP服务器

int CFTP::ftp_quit() 
{ 
	sprintf_s(m_cmd,"QUIT
"); 
	int err = ftp_sendcmd(m_cmd,m_resp,sizeof(m_resp)); 
	if(err)
		return -1;
	//得到返回码
	int code = get_state_code(m_resp);
	//221 Goodbye.
	if(code != 221)
		return -1;	
	return 0; 
} 

退出命令用QUIT表示，发送成功，服务器的返回码是221。

10. 进入指定的FTP目录

int CFTP::ftp_cd( const char* dir )
{ 
	sprintf_s(m_cmd,"CWD %s
",dir);
	int err = ftp_sendcmd(m_cmd,m_resp,sizeof(m_resp)); 
	if(err)
		return -1;
	//得到返回码
	int code = get_state_code(m_resp);
	//250 CWD command successful.
	/*
	550-The system cannot find the file specified. 
	Win32 error:   The system cannot find the file specified. 
	Error details: File system returned an error.
	550 End
	*/
	if(code != 250)
		return -1;
	return 0; 
} 

CWD命令可以进入指定的服务器目录，执行成功后，服务器的返回码是250.

11. 返回上级目录

int CFTP::ftp_cdup() 
{ 
	sprintf_s(m_cmd,"CDUP
"); 
	int err = ftp_sendcmd(m_cmd,m_resp,sizeof(m_resp)); 
	if(err)
		return -1;
	//得到返回码
	int code = get_state_code(m_resp);
	//250 CDUP command successful.
	/*
	550-The system cannot find the file specified. 
	Win32 error:   The system cannot find the file specified. 
	Error details: File system returned an error.
	550 End
	*/
	if(code != 250)
		return -1;
	return 0; 
} 

CDUP命令表示返回上级目录，执行成功的返回码是250.