Am new to in computer vision domain.. I converted 2d image into 1d image.. now i want to apply 1d FFT manually.. can anyone help with the code...?

still now i did

is this correct...?

   if true
    % code
clc;
 close all;
 imtool close all;
 clear;
a=imread('cameraman.tif');
n=imcrop(a);
[r,c]=size(n);
 k=[];
 for i=1:r
     t=a(1,:);
     k=[k;t'];
 end
 figure(1),imshow(k)
  ft=fft(k,1);
 figure(2),imshow(ft)
  end