Why am I getting an “undefined function” error for a function I wrote?

Question

I have written this to determine the n-th Fibonacci number:

function f=fibfun(n)

if n>2
  f=fibfun(n-1)+fibfun(n-2);
else
  f=1;
end

It should work but it doesn't. If I type fibfun(10) then the answer should be 55. But all I get is:

Undefined function 'fibfun' for input arguments of type 'double'.

What does this mean? What am I doing wrong?

Answer 1

It means that MATLAB can't find your function - the directory where you saved the file fibfun.m should either be the current directory or defined in your MATLAB path.

Answer 2

Make sure the file is on your current path.

Use:

addpath(genpath('/path/to/file/'));