#include <stdio.h>

static char *
monthName[12] = {
  "January", "February", "March", "April", "May", "June",
  "July", "August", "September", "October", "November", "December"
};
static char *
dayName[7] = {
  "Sunday", "Monday", "Tuesday", "Wednesday",
  "Thursday", "Friday", "Saturday"
};

/* Our base year is 1900.  Since 1 January 1900 was a Monday, we get the
** following keys for the months.
*/
static int
mkeys[12] = { 1, 4, 4, 0, 2, 5, 0, 3, 6, 1, 4, 6 };
/* This function converts month, date, and year to the day of the week,
** returning an integer between 0 and 6, inclusive, with 0 indicating Sunday.
** This function should work for any year from 1901 to 2099.
*/
static int
DayOfWeek( int month, int date, int year )
{
    int day;

    day = ( year - 1900 ) + ( year - 1900 ) / 4 + mkeys[month] + date - 1;
    /* The above counts the leap day even if it occurs later in the year */
    if(( year > 1900 ) && ( year % 4 == 0 ) && ( month < 2 ) )
      day--;
    day %= 7;
    return day;
}

void
main( int argc, char *argv[] )
{
    int month, date, year, day;

    sscanf( argv[1], "%d", &month ); month--;
    sscanf( argv[2], "%d", &date );
    sscanf( argv[3], "%d", &year );
    day = DayOfWeek( month, date, year );
    printf( "%d %s %d is a %s\n", date, monthName[month], year, dayName[day] );
    return;
}