Assembly stiffness matrix on matlab

Hello everybody, I need some help to assembly three matrix on matlab in order to have the global stiffness matrix of these elements.

I obtain one code on internet, but it doesn't give the good solution ...

 function [K,f]=assem(edof,K,Ke,f,fe) % with Ke: stiffness matrix of elements and  K:global stiffness matrix
    [nie,n]=size(edof);
    t=edof(:,2:n);
    for i = 1:nie
      K(t(i,:),t(i,:)) = K(t(i,:),t(i,:))+Ke;
      if nargin==5
         f(t(i,:))=f(t(i,:))+fe;
      end
    end

This code changes the first matrix of the element 1 ...

Kind regards