function y=Fn(x,p)
x(1)=x;
for i=1:100
if (x(i)>=0&x<p)
    y(i)=x(i)/p;
elseif(x(i)>=p&x(i)<0.5)
    y(i)=(x(i)-p)/(0.5-p);
elseif(x(i)>=0.5&x(i)<1)
     y(i)=Fn(1-x(i),p);
end
x(i+1)=y(i);
i=i+1;
end
plot(y);
%注意：x是在0到1之间的，p是在0到0.5之间的！！

忘了，这句是多余的。可是去掉这句后还是不能运行啊？matlab显示如下代码：
???  Index exceeds matrix dimensions.

Error in ==> F:\MATLAB6.0\work\Fn.m
On line 11  ==> x(i+1)=y(i);

Error in ==> F:\MATLAB6.0\work\Fn.m
On line 9  ==>      y(i)=Fn(1-x(i),p);

Error in ==> F:\MATLAB6.0\work\Fn.m
On line 9  ==>      y(i)=Fn(1-x(i),p);

Error in ==> F:\MATLAB6.0\work\Fnn.m
On line 9  ==>      y(i)=Fn(1-x(i),p);

可是不知为何总是不能运行