Undefined function or variable Matlab

Question

I need to write a fixed point iteration algorithm and it's mostly coded but I'm running into this error:

Undefined function or variable 'g'.

I want to define g as g(x) = 1/2*(1+5/x). However, I'm a matlab n00b and unsure how to do this. Any help would be much appreciated, thanks.

  function [y,k] = fixedpoint(g,p0,tol,max1)
          for k=1:max1
          p = g(p0);
          err = abs(p-p0);
          abserr = abs(sqrt(5)-p);
          ratioerr = abserr/(abs(sqrt(5)-p0));

          if (err<tol)
             break
          end
          p0 = p;

  end
  if (k==max1)
      disp('The algorithm did not converge')
  end
  y = p;

Answer 1

You can define g as a anonymous function

g = @(x)1/2*(1+5/x)

Then call your function fixedpoint in usual way