Time Related library <ctime> analysis

Original works, reproduced please specify the source: http://www.cnblogs.com/shrimp-can/p/5649487.html

I. Types of definitions

1.clock_t: Clock type

2.size_t: unsigned int

3.time_t: Time Type

4.struct TM: Structure, members are as follows:

Member	Type	meaning	Range
tm_sec	int	Seconds after the minute	0-60*
tm_min	int	Minutes after the hour	0-59
tm_hour	int	Hours since midnight	0-23
tm_mday	int	Day of the Month	1-31
tm_mon	int	Months since January	0-11
tm_year	int	years since 1900
tm_wday	int	Days since Sunday	0-6
tm_yday	int	Days since January 1	0-365
tm_isdst	int	Daylight Saving Time Flag

Second, the definition of the macro

1.null: null pointer

2.clocks_per_sec: Clock cycles per second

Three, time operation function

1.clock: clock_t clock (void);

Returns the current clock period, converted to s divided by clocks_per_sec

2.difftime: Double difftime (time_t end, time_t beginning);

Calculates the time unit seconds between geginning and end

3.mktime: time_t mktime (struct TM * timeptr);

Returns the time that timeptr points to, and timeptr updates the other.

  time_t rawtime;   struct  TM * TIMEINFO;   int  year, month, day;  Const   Char  * weekday[] = { "Sunday" ,  "Monday" ,  "Tuesday"   ,  "Wednesday" ,  "Thursday" ,  "Friday" ,  "Saturday" }; printf ( "Enter Year:" ); Fflush (stdout);  scanf ( "%d" , &year); printf ( Enter Month: ); Fflush (stdout);  scanf ( "%d" , &month); printf ( "Enter Day:" ); Fflush (stdout);  scanf ( "%d" , &day);  Time (&rawtime);  Timeinfo = LocalTime (&rawtime);  Timeinfo->tm_year = year-1900;  Timeinfo->tm_mon = month-1;  Timeinfo->tm_mday = day;  Mktime (Timeinfo); printf ( that's a%s.\n ", Weekday[timeinfo->tm_wday]); 
 Output is: 
  

Enter year: 2000Enter month: 5Enter day: 20That day is a Saturday.

4.Time: time_t time (time_t* timer);

Gets the current calendar time, stored in the timer, and returns a null pointer if the fetch fails, returning the current calendar time successfully

Iv. Time Conversion Correlation function

1.asctime: char* asctime (const struct TM * timeptr);

Converts the time of the TM type to the form of a string, returning a string such as www Mmm dd hh:mm:ss yyyy

2.ctime: char* ctime (const time_t * timer);

Converts the time of the time_t type to the form of a string, returning a string such as: Www Mmm dd HH:MM:SS yyyy

3.gmtime: struct TM * gmtime (const time_t * timer);

Converts the time type of the time_t to UTC time, and the corresponding time is stored in the Fabric TM

4.localtime: struct TM * localtime (const time_t * timer);

Use the time in the timer to populate localtime

5.strftime: size_t strftime (char* ptr, size_t maxsize, const char* format, const struct tm* timeptr);

Copies the time of the structure TM description to the string ptr, the maximum maxsize character, as formatted in format. The formate format is as follows:

  time_t rawtime;  struct tm * timeinfo;  char buffer [80];  time (&rawtime);  timeinfo = localtime (&rawtime);  strftime (buffer,80,"Now it‘s %I:%M%p.",timeinfo);  puts (buffer);

 输出为：

Now it‘s 03:21PM.

by

specifier	replaced	Example
%a	Abbreviated Weekday name *	Thu
%A	Full Weekday name *	Thursday
%b	Abbreviated Month name *	Aug
%B	Full month name *	August
%c	Date and Time representation *	Thu Aug 23 14:55:02 2001
%C	Year divided by + truncated to Integer ( 00-99 )	20
%d	Day of the month, zero-padded ( 01-31 )	23
%D	Short MM/DD/YY date, equivalent to%m/%d/%y	08/23/01
%e	Day of the month, space-padded (  1-31 )	23
%F	Short YYYY-MM-DD date, equivalent to%Y-%m-%d	2001-08-23
%g	Week-based year, last digits ( 00-99 )	01
%G	Week-based year	2001
%h	Abbreviated Month name * (same as %b )	Aug
%H	Hour in 24h format ( 00-23 )	14
%I	Hour in 12h format ( 01-12 )	02
%j	Day of the Year ( 001-366 )	235
%m	Month as a decimal number ( 01-12 )	08
%M	Minute ( 00-59 )	55
%n	New-line character ( ‘\n‘ )
%p	AM or PM designation	PM
%r	12-hour clock time *	02:55:02 pm
%R	24-hour time HH:MM , equivalent to%H:%M	14:55
%S	Second ( 00-61 )	02
%t	Horizontal-tab character ( ‘\t‘ )
%T	ISO 8601 time Format ( HH:MM:SS ), equivalent to%H:%M:%S	14:55:02
%u	ISO 8601 Weekday as number with Monday as 1 ( 1-7 )	4
%U	Week number with the first Sunday as the first day of Week one ( 00-53 )	33
%V	ISO 8601 Week number ( 00-53 )	34
%w	Weekday as a decimal number with Sunday as 0 ( 0-6 )	4
%W	Week number with the first Monday as the first day of Week one ( 00-53 )	34
%x	Date representation *	08/23/01
%X	Time representation *	14:55:02
%y	year, last digits ( 00-99 )	01
%Y	Year	2001
%z	ISO 8601 offset from UTC in timezone (1 minute=1, 1 hour=100) If timezone cannot be determined, no characters	+100
%Z	Timezone name or abbreviation * If timezone cannot be determined, no characters	CDT
%%	A Sign %	%

Reference: http://www.cplusplus.com/reference/ctime/

Time Related library <ctime> analysis