How can I get the DFT of this function?

How can I get the DFT of this function?

at 3, 7, 16, 128 points and save the results in vectors.

sorry if my question is silly, but i dont have schoolbecause covid 19

x(n) = u(n) − u(n − 4).

Answer 1

[Nikhil Sonavane]

You may refer to the following code and make changes as per your requirements-

n = 512;
x=[1 1 1 1];
y = fft(x,n);
m = abs(y);
f = (0:length(y)-1)*100/length(y);

You may also refer to the documentation of fft.