Z-bus Matrix Building Algorithm

Write a MATLAB code to build Z-bu matrix if bus data and line data are given.

Here's my attempt, I got wrong result. Could someone please modify it? or wirting another code (the user have to input the bus data and line data matrices only).

clc;
clear all;

         % | From | To | R | X | gsh | B | T|ysh
         % | Bus | Bus | pu | pu | pu | pu | ph-sh
LD= [ 1  2 0 0.8	0 0
             1  3 0 0.4 0 0
             2  3 0 0.4 0 0];
         
r=1.05;
angle=5*(pi/180);
[x,y]=pol2cart(angle,r) ;
t=x+i*y;

fbus=LD(:,1);             % Reading from bus
tbus=LD(:,2);             % Reading to bus
r = LD(:,3);              % Resistance, R...
x = LD(:,4);              % Reactance, X...
gsh=LD(:,5);
B = 1i*LD(:,6);           % Ground Admittance
%T=LD(:,7);
Zl=1/(r+(1i*x));        
%     fb tb Eg  Xg  Zd
BD = [1   0  0  inf 0.2i
      2   0  0  inf 0.4i 
      2   3  0  inf 1]  
fb=BD(:,1);  
tb=BD(:,2);  
Eg=BD(:,3);
Xg=1i*BD(:,4);
Zd=BD(:,5);       

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

busses=max(max(fbus),max(tbus));
%zold=zeros(busses,busses)
z=zeros(busses);
zmod=z
for b=1:busses
    z(b,b) = Zd(b)  ; %diagonal matrix
end

for b=1:busses

    %add col and row 
    for i=1:busses-1
        
        if tb~=0
        
          a=transpose (z(:,fb(b)))    %column to add
          %row to add
          b=transpose (a)
          zmod=[zmod,a;b]
        
        end
        
        if tb==0    %special case: add col and row of zero elements
            zmod=[zmod,zeros(i,1);zeros(1,i+1)];
        end
        
        NS=size(zmod)
        zmod(NS,NS) = Zd(b) + zmod(fb(b),fb(b)) %last element of the mod. matrix   
end
end
zmod

[Fatima Yusuf]

The code above is just for the bus data, I didn't include the lines yet.