Bisection method- code stops after one iteration

Hi, my code doesn't seem to continue beyond the first iteration of the bisection method in my loop. I also am not getting the right answer. I'm not sure where the mistake is.

function c = findroot(f,a,b,e)
% a is the initial value
% b is the final value
% e is the tolerance

if f(a)*f(b)>0
    error('f(a) and f(b) must have opposite signs')
end

c = (a+b)/2;

while abs(b-c) <= e;
    f = f(c);
    break
    if f(a)*f(c) <= 0;
      c = b;
        f(c) = f(b);
    else 
      c = a;
        f(c) = f(a);
    end
end

end

I am calling the following in the command window:

>> f = @(x) x.^2-x-1;

>> findroot(f, 1, 2, 0.001)

Answer 1

[Torsten]

function c = findroot(f,a,b,e)
% a is the initial value
% b is the final value
% e is the tolerance

left = a;
right = b;
middle = (left+right)/2;
fleft = f(left);
fright = f(right);
fmiddle = f(middle);

if fleft*fright > 0
    error('f(a) and f(b) must have opposite signs')
end

while right-left >= e && abs(fmiddle) >= e
    if fmiddle*fleft <= 0
      right = middle;
        fright = fmiddle;
    else 
      left = middle;
        fleft = fmiddle;
    end
    middle = (left+right)/2;
    fmiddle = f(middle);
end

c = middle;

end

Best wishes

Torsten.

[MG]

Hi Torsten. Thank you for the code, I actually figured out the problem myself shortly after posting the question.