Problem with cubic spline

I got this message:

Unable to perform assignment because the left and right sides have a different number of elements.

Error in NCS_Construct (line 16)

h(1:5) = x(2:n)-x(1:n-1) % lengths of intervals [x_i, x_{i+1}]

Code

x = [0, 1, 2, 3]; % x coordinates of the data points
n = length(x);

f = inline('-exp(-4*x)+exp(-.5*x)');
%f = inline('(x-3).^2');  % the actual function that the data points come from.
y = f(x)

% Use the colon command (:) to construct vectors h and r 
% that contain h_i and r_i as components
h(1:5) = x(2:n)-x(1:n-1) % lengths of intervals [x_i, x_{i+1}]
r(1:5) = y(2:n)-y(1:n-1) % differences y_{i+1}-y_i

% Define A to be the zero matrix of size nxn
A = zeros(n);

% Construct A given in (1b) for the natural cubic spline. 
% You will have to change this for the clamped cubic spline
A(1,1) = 1; %CHANGE THIS FOR THE CLAMPED CUBIC SPLINE
A(2:n-1, 1:n-2) = diag(h(1:3));
A(2:n-1, 2:n-1) = A(2:n-1, 2:n-1)+diag(2.0*(h(1:n-2)+h(2:n-1)));
A(2:n-1, 3:n) = A(2:n-1, 3:n)+diag(h(2:n-1));

Answer 1

[John D'Errico]

THINK! What is n?

x = [0, 1, 2, 3]; % x coordinates of the data points
n = length(x);

n is 4.

Then what do you do?

h(1:5) = x(2:n)-x(1:n-1) % lengths of intervals [x_i, x_{i+1}]

How long is the vector 1:5? What was the error message? How many elements are on the right hand side of the equality? (Hint: 4)

Now read the error message again.