nx=180;
x=[0:1/nx:1];
dx=x(2)-x(1);
x=[x 1+dx];
nx=size(x,2);
f(:,1)=(sin(2*pi*x));
time(1)=0;
dt=0.5*dx;
nt=floor(1/dt+1);
coef=dt/2/dx;
for it=2:nt
	 f(2:nx-1,it)=f(2:nx-1,it-1)-coef*(f(3:nx,it-1)-f(1:nx-2,it-1));
f(1,it)=f(nx-1,it);f(nx,it)=f(2,it);
time(it)=time(it-1)+dt;
endfor
plot(x,f(:,1),"linewidth",2,x,f(:,nt),"-o","linewidth",2);
xlabel ("x");
ylabel ("f");
axis ([0 1 -2 2]);
legend ("exata","numerica");