"Function definitions are not permitted in this context." ? bisection

I am really new to MATLAB. I'm trying to write/test a bisection program that determines T as a function of C. I have initial guesses and will test some cases in the command window, but my code doesn't execute. I'm getting this error on the first line: "Function definitions are not permitted in this context." I'm not really sure if it's a file type error or a syntax error and how to fix it. Some help would be appreciated.

Thanks!

function [TofC] = TEval(osf)

    % temp absolute
    U = 40+273.15;
    L = 0+273.15;

    % disp if no bracketing for a guess
    if 0 < fTabs(L,osf)*fTabs(U,osf)
       error('brackets')
    end
    end

    r = L;

    %iterate 1 to 10
    for i=1:10
        rInitial=r;
       r = 0.5*(L+U);
        % middle val
        if r~=0, z = 100 * abs((r-rInitial)/r);
        end
   %check specifies test values from text 
   check=fTabs(r,osf)*fTabs(L,osf);
     if check < 0
          U = r;

        elseif check > 0
            r = L;

        else
           z = 0;
       end
    end

    TofC = -273.15 + r;   

    function [k] = fTabs(Tabs,osf)
        k = -139.3441 + ((1.5757e5)/Tabs) - ((6.64231e7)/Tabs^2);
        k = k - ((8.62195e11)/Tabs^4) + ((1.2438e10)/Tabs^3);
        k = k - log(osf);
    end

Answer 1

[Walter Roberson]

You have to write that code into a file named TEval.m

Answer 2

[Geoff Hayes]

Amanda - you seem to have an extra end after the first if statement

    if 0 < fTabs(L,osf)*fTabs(U,osf)
       error('brackets')
    end
    end

Remove one of these and that will almost fix the problem. Since you have two functions, one which uses the other, with the second one "nested" within the first, then you need to close the first function with an end too

 function [TofC] = TEval(osf)
     % function code

     function [k] = fTabs(Tabs,osf)
        % nested function code
     end
 end % <---- need this end

Answer 3

[Star Strider]

You most likely need to save your functions to their own individual ‘.m’ files. Then you can call them as you would any other function. See the documentation on Function Basics (link) for your MATLAB version.