it will soon be easter. this year, easter sunday is on April 20.

the idea is to write an easter sunday calculation program valid for years 1900-2099 on the 25C (ie in 50 steps or less!).

to make it more interesting, i've already had a go, but my answer is incomplete. completely different approaches are allowed as long as they work!

i've managed to simplify a formula down to the following logic:

d =(204 - 11*(y%19))%30;

if (d < 28) ++d;

return d+27-(5*y/4+d)%7;

where `y' is the input year. the result `d' is the day number from march, where d > 31 implies april (d-31). after some struggle, i write:

sto0 1 9 / int 1 9 * rcl0 - 1 1 * 2 0 4 + sto1 3 0 / int 3 0 * sto-1 2 8 sto2 rcl1 x>=y? gto35 1 + rcl0 5 * 4 / int sto-2 + 7 / int 7 * rcl2 +

which works but always returns the answer + 1 :-)

be sure to test 1954 (which is April 18).

happy easter!