%
%  Simple code to iterate Henon Map 
%
clear
clf
a=input(' Give value for a: ');
b=input(' Give value for b: ');
nmax=input(' Give number of iterations: ');
x(1)=input(' Give starting x: ');
y(1)=input(' Give starting y: ');
plot(x,y,'k.','markersize',2)
for i=1:nmax
  x(i+1)=y(i)+1-a*x(i)*x(i);
  y(i+1)=b*x(i);
end
plot(x,y,'r.','markersize',2)
hold on
ll=length(x);
plot(x(ll-10:ll),y(ll-10:ll),'bo')
title(' Circles show last 10 iterations');
hold off