MATLAB: How i can find the DTFT of sequence without using fft inbuilt function

Question

i am trying this code,

    clc; clear; close all;
    n = 0:1:100;
    x = ((n >= 0) - (n >= 5));
    stem(n, x);
    len = length(x);
    X = zeros(1, len);
    for w = 0:2*pi*len  
       for n = 0:len
          X(w+1) = X(w+1) + x(w+1)*exp(-1j*w*n);
       end
    end

Answer 1

w=-pi:0.01:pi;
n=0:50;
x=[1 2 3 4];
for i=1:length(w);
    X(i)=0;
    for k=1:length(x);
          X(i)=X(i)+x(k).*exp(-j.*w(i).*n(k));
      end
  end
plot(w,X);
title('DTFT');