#include <stdio.h>
#include <time.h>

static const char *week_day[] = {
    "Sunday", "Monday", "Tuesday", "Wednesday",
    "Thursday", "Friday", "Saturday"
};

void main()
  {
    struct tm new_year;

    new_year.tm_year  = 2001 - 1900;
    new_year.tm_mon   = 0;
    new_year.tm_mday  = 1;
    new_year.tm_hour  = 0;
    new_year.tm_min   = 0;
    new_year.tm_sec   = 0;
    new_year.tm_isdst = 0;
    mktime( &new_year );
    printf( "The 21st century began on a %s\n",
             week_day[ new_year.tm_wday ] );
  }