MATLAB: Error using feval .

feval

'pergjysmim.m'
function [alfa,k]=pergjysmim(fun,a,b,tol,max_iter) 
  % funksioni [alfa,k]=pergjysmim(fun,a,b,tol,max_iter) 
  % fun eshte variabel string per emrin e funksionit 
  % a dhe b jane skajet e segmentit qe permban rrenjen 
  % tol eshte gabimi (toleranca) i lejuar per rrenjen e gjetur 
  % max_iter eshte numri maksimal i iteracioneve te lejuara 
  % alfa eshte perafrimi i gjetur i rrenjes me gabim
  % me te vogel se tol
  % k numeron iteracionet e kryera 
    fa=feval(fun,a); 
    fb=feval(fun,b); 
    if sign(fa)*sign(fb)>0 
        error('Funksioni fun nuk ndryshon shenje ne [a,b]'); 
    end 
    k=1; 
    while k<=max_iter 
        c=a+(b-a)/2; % kjo eshte me mire se c=(a+b)/2;  
          if abs(b-a)/2<tol 
            alfa=c; 
            return; 
          end
        k=k+1; 
        fc=feval(fun,c); 
        if sign(fa)*sign(fc)>0 
            a=c; fa=fc; 
        elseif sign(fa)*sign(fc)<0 
            b=c; fb=fc; 
        else 
            disp('rrenja eshte gjetur me saktesine e precizionit te kompjuterit') 
            alfa=c; 
            return; 
        end 
    end 
    error('Eshte tejkaluar numri maksimal i iteracioneve te lejuara-programi pergjysmim ka mbaruar egzekutimin')
'funx.m'
function y=funx(x) 
y=x^4+2*x^3-x-1;
end
Command Window
>>[zgj,iter]=pergjysmim('funx',0,1,5e-07,100)
Error using feval
Error: File: funx.m Line: 2 Column: 8
Unexpected MATLAB expression.
Error in pergjysmim (line 12)
fa=feval(fun,a); % llogarit vleren e funksionit ne a

Best Answer

 Error: File: funx.m Line: 2 Column: 8
 y=x^4+2*x^3-x-1;
The 8th column is the * . This is a valid Matlab operator and it is not clear, what the problem is. I've tried to copy&paste the character to check, if it is char(42) or any strange Unicode character e.g. copied from a PDF, but it seems to be okay.
Therefore Guillaume's idea could be right: This is not the used file, but another one, which contains a strange character in the mentioned location. If not, delete this character and type it again.
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