Plot the magnitude plot of Discrete Time Fourier Transform | MATLAB

%Code:-

clc

clear all

close all

n=-20:20;

xn=cos(2*pi*0.2*n);

w=-pi:0.01:pi;

for i=1:length(w)

    xw(i)=sum(xn.*exp(-1i*w(i)*n));

end

plot(w,abs(xw));