I think the array you mentioned is temporary array not normal variable array.
data _null_;
infile 'c:\grid.txt' end=last;
array a{20,20} _temporary_;
array x{20} x1-x20;
input x1-x20;
do k=1 to 20;
a{_n_,k}=x{k};
end;
if last then do;
do i=1 to 20;
do j=1 to 20;
put a{i,j} @ ;
end;
put / ;
end;
end;
run;
Ksharp