function mixed = exc1( img_path, out_path )

im = imread(img_path);

fprintf('első verzió:');
tic
for i = 1:size(im,1)
   for j = 1:size(im,2)
       red = im(i,j,1);
       im(i,j,1) = im(i,j,3);
       im(i,j,3) = red;
   end
end
toc

if exist(out_path, 'dir') == 7
    [path, name, ext] = fileparts(img_path);
    imwrite(im,strcat(out_path, name, '_mixed', ext));
end

mixed = im;

fprintf('második verzió: ');
tic
R = im(:,:,1);
im(:,:,1) = im(:,:,3);
im(:,:,3) = R;
toc

imshow(im);

end