runge kutta segundo orden

clc
clear
f=inline('x-y')
x0=0;
y0=2;
xx=1;
n=4;
i=1;
h=(xx-x0)/n;
disp('-n-----x-------------y-----k0--------k1')
while i<=n
x1=x0+h;
k0=f(x0,y0);
k1=f(x0+h,y0+h*k0);
y1=y0+(h/2)*(k0+k1);
fprintf('\n%2i %10.5f %10.5f %10.5f %10.5f \n ',i,x1,y1,k0,k1)
y0=y1;
x0=x1;
i=i+1;
end
fprintf('\n y(1)= %2f\n ',y1)