||It returns a pointer to a string that represents the day and time of the structure timeptr.
||It returns the processor clock time used since the beginning of an implementation-defined era.
||It returns a string representing the localtime based on the argument timer.
||It returns the difference of seconds between time1 and time2.
||It converts the value of timer into the structure tm and expressed in Coordinated Universal Time (UTC).
||It converts the value of timer into the structure tm and expressed in the local time zone.
||It converts the structure pointed to by timeptr into a time_t value according to the local time zone.
||It formats the time represented in the structure timeptr according to the formatting rules defined in format and stored into str.
||It calculates the current calendar time and encodes it into time_t format.