Index Error while writing a function to call ODE's

I am writing a code that uses the switch function to call various methods to solving ODEs. Every time I call the function I get a ton of errors. The first one is always "index exceeds matrix dimensions" and the rest just point to certain lines. How do I get rid of the first error?

switch value

    case 0
        method=@Emethod; 
    case 1
        method=@Rmethod;  
end

for i=1:N

    y(i+1)= method(y(i),f,x(i),h);
    x(i+1)=x(i)+h;
end

*In a different tab I have the equations for Emethod and Rmethod . For example:*

function y = Emethod(y,f,x,h)

k1 = f(x(i),y(i)); y(i+1) = (y(i)+h*k1);

end

*There also seems to be a problem with the line for k1*

Any suggestions?