periodic boundary conditions in matrix

Hi everyone, i want to ask about a question n*n matrix like Q[A C 0 0 0 0 0....C ; C A C 0 0 0 0....0 ; 0 C A C 0 0 0....0 ; ...... ; ...... ; 0 0 0 0 0......C A ; A C 0 0........0 C ; A C 0 0....... 0 C] which is Q(1)=Q(n+1), Q(n)=Q(2n) and so on... It is periodic and A and C is not constant. I have some difficulties writing in MATLAB

Please help me, thanks