What is the wrong

%% Jacobi Method
%% Solution of x in Ax=b using Jacobi Method
% * Initailize 'A' 'b' & intial guess 'x' %% A=[2.08 -1 0 0;-1 2.08 -1 0;0 -1 2.08 -1;0 0 -1 2.08]; b=[200.8;0.8;0.8;40.8]' 
b=[200.8;0.8;0.8;40.8]'
x=[0 0 0 0]'
n=size(x,1);
normVal=Inf;
%%
% * Tolerence for method
tol=1e-5;
itr=0;
%% Algorithm: Jacobi Method
%%
while normVal>tol
    xold=x;
    for i=1:n
        sigma=0;
        for j=1:n
            if j~=i
                sigma=sigma+A(i,j)*x(j);
            end
        end
        x(i)=(1/A(i,i))*(b(i)-sigma);
    end
    itr=itr+1;
    normVal=abs(xold-x);
end
%%
fprintf('Solution of the system is : \n%f\n%f\n%f\n%f in %d iterations',x,itr);

[DGM]

I have no idea. If you want someone to debug your code, present it in a format that can actually be tested.

I don't know what's wrong with it. After much reformatting, it runs without errors. If the results aren't what you expect, I wouldn't know. You didn't describe the problem or mention any errors.

[Walter Roberson]

I had to guess about the spacing when I reformatted it to make it readable.

[DGM]

Are these occasional imploded posts a consequence of some issue with char encoding and user locale?

[Walter Roberson]

I don't think so. You get bad formatting like that if you post code on the desktop without using the > button to create acode region, as the site supposes you have typed in conversational text.

(If you happen to post code on mobile, then the result depends upon whether the first character of the paragraph is space or not; if it is then the paragraph up to the next empty line is formatted as code.)