When is Easter?Plot a bar graph of the dates of Easter during the 21-st century.

well ,the Easter occur 22 in March ,and 78 in April during the 21-st century . but I don't know how to solve those question .

• Plot a bar graph of the dates of Easter during the 21-st century.
• How many different dates does can Easter occur ?
• What's the earliest in the year ?what's the latest ?
• Is the date of Easter a periodic function of the year number ?

function bar4easter
f=zeros(1,100);
y=2000;
for k=1:100
    f(k)=easter(y);
    y=y+1;
end
[~,m,d,~,~,~]=datevec(f);
count3=0;
count4=0;
for k=1:100
    if m(k)==3
        count3=count3+1;
    else
        count4=count4+1;
    end
end
count3
count4
hist(m)

and this is Easter.m below .

 function dn = easter(y)
  % EASTER  Date of Easter.
  % EASTER(y) is the datenum of Easter in year y.
  % Ref: Donald Knuth, The Art of Computer Programming,
  %      Fundamental Algorithms, pp. 155-156.

% Golden number in 19-year Metonic cycle.
g = mod(y,19) + 1;

% Century number.
c = floor(y/100) + 1;

% Corrections for leap years and moon's orbit.
x = floor(3*c/4) - 12;
z = floor((8*c+5)/25) - 5;

% Epact.
e = mod(11*g+20+z-x,30);
if (e==25 && g>11 || e==24), e = e + 1; end

% Full moon.
n = 44 - e;
if n < 21, n = n + 30; end

% Find a Sunday.
d = floor(5*y/4) - x - 10;

% Easter is a Sunday in March or April.
d = n + 7 - mod(d+n,7);
dn = datenum(y,3,d);