public static int dayOfWeek(int month, int day, int year) {
    int n;
    n = day;
    n += 2*month;
    n += (3*(month+1)/5);
    n += year;
    n += year/4;
    n -= year/100;
    n += year/400;
    n += 2;
   return n%7;
  }

  public static void testDayOfWeek() {
    System.out.print("Testing dayOfWeek... ");
    // On 2/5/2006, the Steelers won Super Bowl XL on a Sunday!
    assert(dayOfWeek(2, 5, 2006) == 1);
    // On 6/15/1215, the Magna Carta was signed on a Monday!
    assert(dayOfWeek(6, 15, 1215) == 2);
    // On 3/11/1952, the author Douglas Adams was born on a Tuesday!
    assert(dayOfWeek(3, 11, 1952) == 3);
    // on 4/12/1961, Yuri Gagarin became the first man in space, on a Wednesday!
    assert(dayOfWeek(4, 12, 1961) == 4);
    // On 7/4/1776, the Declaration of Independence was signed on a Thursday!
    assert(dayOfWeek(7, 4, 1776) == 5);
    // on 1/2/1920, Isaac Asimov was born on a Friday!
    assert(dayOfWeek(1, 2, 1920) == 6);
    // on 10/11/1975, Saturday Night Live debuted on a Saturday (of course)!
    assert(dayOfWeek(10, 11, 1975) == 7);
    System.out.println("Passed all tests!");
  }