Explicity method for diffusion problem

I am totally new in matlab and I have to write the explicit method for diffusion in matlab. I have did what i know and learned in matlab by different resources.

Could you guys check the code and see if it is good.

l=0.2;      % length in meter
nx=40;      % number of thickness step 
nt=10;      % number of time step
dx=l/(nx-1);
dt=0.1;

T_in=22;    % C
h_out=34;  % W./m2
h_in=10;
T_out=34;       %  outdoor temperature
abs=0.2;       % wall absorbility 
Gt=1140;        % radiation
k=0.7;            % conductivity
Cp=0.84;       %capacity
roh=1600;       % density

alfa=k/(Cp*roh);
Te=T_out*(abs*Gt/h_out);  % soalr temperture or ambient temp

Bo=h_out*dx/k;
Bi=h_in*dx/k;
f=alfa*dt/(dx*dx);

T(i)=T(i,m);
for i=1:nt
Tnew=zeros(1,nx);
    for m=2:(nx-1)
 Tnew(m)=T(m)+1;

   T(i+1,1)=Ts-Bi*(Te-Ts)+(1/(2*f))*Ts;
    T(i+1,2)=(1/(f*2))*(T(i+1,1))-(1/f)*(T(i,1)-Ts); 
   T(i+1,m+1)=(1/(f*2))*T(i+1,m)-(1/f)*(T(i,m)-T(i+1,m-1)); 
    T(i+1,MM+1)=T(i+1,MM)-Bo*(T_in-T(i+1,MM))+(1/(2*f))*(T(i+1,MM)-T(i,MM)); 
      end
  end

1/f;
T(MM,:);

figure(1)
plot(T(1,:),'r')
hold on
plot(T(3,:),'y')
hold on
plot(T(5,:),'g')
hold on
plot(T(7,:),'b')
hold off
legend('1secs','3secs','5secs','7secs')