How to check the freqeuncy response of a boxcar filter?

Hi, I am performing a lowpass filtering with two different filters. a) window i.e. box car b) butter filter. For butter, I know how to see the frequency response, but how to see the freqeuncy response of boxcar filter?

clear all; clc;
fs =2000;
fc =20/(fs/2);   
N = 1/fc;
h = boxcar(N);  % 1/N = fc
h = h/sum(h);
%filtered_signal = filtfilt(h, 1, signal));

butter

clc; clear all;
fs = 2000;
filtorder = 6; bw_butter =20;
[bcoeff,acoeff] = butter(filtorder,bw_butter/fs*2);

figure()
freqz(bcoeff,acoeff,[],fs)
xlim([0 200])

%filtered_signal = filtfilt(bcoeff,acoeff, signal));

Answer 1

[Chunru]

clear all; clc;
fs =2000;
fc =20/(fs/2);   
N = 1/fc;
h = boxcar(N);  % 1/N = fc
h = h/sum(h);
bcoeff = h; 
acoeff = 1;
freqz(bcoeff,acoeff,[],fs)

%xlim([0 200])