C + + lesson Tenth: standard C time and date functions

Asctime ()	Time Text Format
Clock ()	Returns the elapsed time since the program started running
CTime ()	Return a specific format time
Difftime ()	The interval between two moments
Gmtime ()	Returns a pointer to the current GMT point
LocalTime ()	Returns a pointer to the current time
Mktime ()	Returns the calendar format for a specified time
Strftime ()	Returns a single element of a date and time
Time ()	Returns the current calendar time of the system

Asctime

Grammar:

#include <time.h> Char *asctime (const struct TM *ptr);

Function: The function converts the time structure pointed to by PTR into the following string:

Day Month date Hours:minutes:seconds year\n\0

For example:

Mon June 26 12:03:53 2000

Related Topics:
LocalTime (), Gmtime (), Time (), and CTime ().

Clock

Syntax:

#include <time.h> clock_t clock (void);

Function: The function returns the processor time since the program started running, and returns 1 if no information is available. The conversion return value is in seconds, and the return value is divided by Clocks_per_second. (Note: If the compiler is POSIX-compliant, Clocks_per_second is defined as 1000000.)

Related Topics:
Time (), Asctime (), and CTime ().

CTime

Syntax:

#include <time.h> Char *ctime (const time_t *time);

Function: The function conversion parameter time is the local temporal format:

Day Month date Hours:minutes:seconds year\n\0

CTime () equivalent

Asctime (localtime (TP));

Related Topics:
LocalTime (), Gmtime (), Time (), and Asctime ().

Difftime

Syntax:

#include <time.h> Double Difftime (time_t time2, time_t time1);

Function: The function returns the number of seconds that the difference between the time parameter time2 and time1 .

Related Topics:
LocalTime (), Gmtime (), Time (), and Asctime ().

Gmtime

Syntax:

#include <time.h> struct TM *gmtime (const time_t *time);

Function: The function returns the given uniform world time (usually GMT) if the system does not support the unified world time system to return NULL. Warning!

Related Topics:
LocalTime (), Time (), and Asctime ().

LocalTime

Syntax:

#include <time.h> struct TM *localtime (const time_t *time);

Function: The function returns the local calendar time. Warning!

Related Topics:
Gmtime (), Time (), and Asctime ().

Mktime

Syntax:

#include <time.h> time_t mktime (struct TM *time);

Function: The function converts The local time of the type to the time of the calendar and returns the result. If an error occurs, return-1.

Related Topics:
Time (), Gmtime (), Asctime (), and CTime ().

Strftime

Syntax:

#include <time.h> size_t strftime (char *str, size_t maxsize, const char *FMT, struct TM *time);

Function: The function formats the parameters of the time type as datetime information in the format set by the parameter FMT , and then stores it in the string str (up to maxsize characters). The code used to set the different types of time is:

Code	Meaning
%a	Abbreviated form of the week
%A	Full form of the week
%b	The abbreviated form of the month
%B	Full form of the month
%c	The abbreviated form of the month
%d	Day ordinal of the month (1-31)
%H	Hours, 24-hour format (0-23)
%I	Hours, 12-hour format (1-12)
%j	Day of the Year (1-366)
%m	Month (1-12). Note: Some versions of Microsoft Visual C + + may use a value range of 0-11.
%M	Minutes (0-59)
%p	Morning or afternoon in local time (AM or PM)
%s	Seconds (0-59)
%u	Week of the year, Sunday is the first day of the week
%w	Numeric representation of the Day of the week (0-6, Sunday =0)
%W	Week of the year, Sunday is the first day of the week
%x	Standard date string
%x	Standard Time string
%y	Year (0-99)
%Y	Year expressed in Ccyy (eg: 2004)
%Z	Time Zone Name
%%	Percent Sign

The function strftime () returns a value of the number of characters in the result string str , and returns zero if an error occurs.

Related Topics:
Time (), localtime (), and Gmtime ().

Time

Syntax:

#include <time.h> time_t time (time_t *time);

Function: The function returns the current time if an error occurs and returns zero. If a parameter is given, the current time is stored in the parameter.

Related Topics:
LocalTime (), Gmtime (), strftime (), CTime (),

C + + lesson Tenth: standard C time and date functions