Date to Day of the week algorithm?

Question

What is the algorithm that, given a day, month and year, returns a day of the week?

Answer 1

One of the easiest algorithm for this is Tomohiko Sakamoto Algorithm:

static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
y -= m < 3;
return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;
}

Check this out: https://iq.opengenus.org/tomohiko-sakamoto-algorithm/

I found Wang's method also interesting

w = (d - d^(m) + y^ - y* + [y^/4 - y*/2] - 2( c mod 4)) mod 7

http://rmm.ludus-opuscula.org/PDF_Files/Wang_Day_5_8(3_2015)_high.pdf This pdf is really helpful too.

Thanks!