function comparison

for k=0:13
    N=2^k;
    [t,x]=euler(@odefun1, [0 1],1,N);
    eulervals(k+1)=x(N+1);
    [t,x]=heun(@odefun1, [0 1],1,N);
    heunvals(k+1)=x(N+1);
end


NN=2.^[0:13];
eulererr=abs(eulervals-exp(1));
heunerr=abs(heunvals-exp(1));
hold off;
clear figure;
loglog(NN, eulererr,'+');
hold on;
loglog(NN, heunerr,'o');
end