square lattice

it's a matlab program that should implement a half filled square lattice of variable size L (the total filling is L²/2, the sites of the lattice are alternatively filled-1-and empty-0-) with an array named [l,i,j] where l is the state label. i, the horizontal axis and j the vertical axis.
the code is a for loop for i and for j
that return for each selected i and j a state label=0 or 1 (the site associated to coordinate (i,j) is filled or empty).