function [x, v] = ftfs(a, lambda, M, u0, N)
%
% Forward-time forward-space scheme
% for the one-way wave equation u_t + a u_x = 0 on [0,1] with periodic
% boundary condition
% and initial value u0(x)
%
% Note: h = 1/M, lambda = k/h and N = T/k
%

x = linspace(0, 1, M+1);
v = u0(x);

vtmp = zeros(1,M+1);
for n = 1:N
    
    for m = 1:M
        vtmp(m) = (1 + a*lambda)*v(m) - a*lambda*v(m+1);
    end
    vtmp(M+1) = vtmp(1);
    
    v = vtmp;
    
end