strftime - format date and time

strftime - format date and time
       #include 

       size_t strftime(char *s, size_t max, const char *format,
                           const struct tm *tm);
       The strftime() function formats the broken-down time tm according to the format specifica-
       tion format and places the result in the character array s of size max.

       The strftime() function returns the number of  characters  placed  in  the  array  s,  not
       including  the  terminating  NUL character, provided the string, including the terminating
       NUL, fits.  Otherwise, it returns 0, and the contents of the array is undefined. 
       Note that the return value 0 does not necessarily indicate an error; for example, in  many
       locales %p yields an empty string.
For more details check man pages.