I am trying to write a code for Forward Substitution in Matlab. I keep getting an error that says 'Index in position 2 exceeds array bounds (must not exceed 3)'. This occurs when working with a square matrix of 4X4. How can I fix my code to prevent this error?

q function x = FowardSubs (a, b) A is a lower triangular matrix B is a solution or column vector The function returns the solution as a column vector %} n = length(b) % length of column vector x(1, 1) b(1) / a (1,1); for m = 2:n x(m, 1) = (b (m) a(m, 1:m-1)*x(1:m-1,1))./a(m,m); end