Bisection Method For Finding Roots Of equation Matlab Code

fed up of doing calculations by hand to find the roots of an equation by "BISECTION METHOD" (one of  the bracketing techniques to solve an equation) the solution is simple and reliable write a piece of MATLAB code.Cant do this???? thats what i am here for !! here is the required code !! this code will
1.find the mean value at each iteration
2.plot the graph of true error
3.plot graph of approximate error
change the function and initial bracket according to your requirements!!
here is the code




clc
clear all
close all
xl=0;
xu=1;
xr=0;
ethresh=2;
xt=0.5671;
et=[];
ea=[];
for i=1:10
f_xl = exp(-xl)-xl;
f_xu = exp(-xu)-xu;
bracket = [xl xu];
xrold=xr;
xr=(xl+xu)/2
ea(i)=abs((xr-xrold)*100/xr);
et(i)=(xr-xt)/xr;
f_xr=exp(-xr)-xr;


if(f_xl*f_xr<0)
    xu=xr;
else if(f_xu*f_xr<0)
       xl=xr;
    else
        ea=0;
    end
    
    next_bracket=[xl xu]
end
end
plot(1:length(et),et,'r')
grid on
hold on
plot(1:length(ea),ea,'b')