fftdemo14.m

% The 2D signal
y = [ 1 -1 4 8 zeros(1,12)];
N = length(y);

% Plot unshifted signal
figure
subplot(2,1,1), stem(y), title('Unshifted Signal')

% Frequency domain samples
f = 0:N-1;

% The shift
k = 6;

% The exponential
shft = exp((-2*pi*i/N)*k*f);

% The shifting operation
Y = fft(y);
Yshft = Y.*shft;
yshft = real(ifft(Yshft));
% The real part of the ifft must be selected because sometimes due to
% computational errors on the part of the computer there will be a very 
% small imaginary residual

subplot(2,1,2), stem(yshft), title('Shifted Signal')