N = 4; % change N as needed, for any n x n matrix
A = []; % yung matrix. Kahit i-hardcode mo na HAHAHAHHA
b = []; % yung b na vector sa Ax = b, hardcode mo na lang din HAHA
x = [0;0;0;0]; % dito ilalagay yung new values ni x, initialize to initial guess ng x(0)
xold = [0;0;0;0]; % for storing the old values of x
tolerance = 1e-15; % change tolerance as needed

% J A C O B I
while (norm(b-A*x) > tolerance)
	xold = x;
 	for a = 1:N
 		x(a) = b(a);
 		for k = 1:N
 			if (a==k)
 				continue
 			end
 			x(a) -= A(a,k)*xold(k);
 		end
 		x(a) /= A(a,a);
 	end
end