5.18 How to print elements of a matrix?

restart; 
a:=Matrix([  [2,3,4],[4,5,6]   ]); 
nRow,nCol :=LinearAlgebra[Dimension](a); 
for i from 1 to nRow do 
    for j from 1 to nCol do 
        printf("a(%d,%d)=%d\n",i,j,a[i,j]); 
    end do; 
end do; 
 
a(1,1)=2 
a(1,2)=3 
a(1,3)=4 
a(2,1)=4 
a(2,2)=5 
a(2,3)=6