CTime ct = CTime::GetCurrentTime();

CString str = ct.Format("%Y-%m_%d %H-%M-%S");

输出为：str="2006-04-23 15-21-30"

%a 
Abbreviated weekday name 
%A 
Full weekday name 
%b 
Abbreviated month name 
%B 
Full month name 
%c 
Date and time representation appropriate for locale 
%d 
Day of month as decimal number (01 – 31) 
%H 
Hour in 24-hour format (00 – 23) 
%I 
Hour in 12-hour format (01 – 12) 
%j 
Day of year as decimal number (001 – 366) 
%m 
Month as decimal number (01 – 12) 
%M 
Minute as decimal number (00 – 59) 
%p 
Current locale's A.M./P.M. indicator for 12-hour clock 
%S 
Second as decimal number (00 – 59) 
%U 
Week of year as decimal number, with Sunday as first day of week (00 – 53) 
%w 
Weekday as decimal number (0 – 6; Sunday is 0) 
%W 
Week of year as decimal number, with Monday as first day of week (00 – 53) 
%x 
Date representation for current locale 
%X 
Time representation for current locale 
%y 
Year without century, as decimal number (00 – 99) 
%Y 
Year with century, as decimal number 
%z, %Z 
Either the time-zone name or time zone abbreviation, depending on registry settings; no characters if time zone is unknown 
%% 
Percent sign

// Example for CTime::Format and CTime::FormatGmt
CTime t( 1999, 3, 19, 22, 15, 0 ); 
// 10:15 PM March 19, 1999
CString s = t.Format( "%A, %B %d, %Y" );
ATLASSERT( s == "Friday, March 19, 1999" );