Image is rotating but becoming whitish!

I am trying to rotate the image without using imrotate. Logic is fine and image is rotating as well. But image is getting noise or something and becoming whitish. Any help would be appreciated as I am a beginner in this. Thank you.

% Read input image
img = imread('dog.jpeg');

img_90 = rotate90(img);
img_180 = rotate90(img_90);

% display result
subplot(1, 3, 1), imshow(img), title('Original Image');
subplot(1, 3, 2), imshow(img_90), title('Rotated (90)');
subplot(1, 3, 3), imshow(img_180), title('Rotated (180)');

function rotated = rotate90(img)
    [r, c, z] = size(img);

    % Create dummy matrix to store updated matrix.
    rotated(c, r, z) = 0;

    % Loop to access each element of matrix.
    for plane = 1:z
        for i = 1:r
            for j = 1:c
                % Logic to rotate Matrix A by 90 degree.
                rotated(c-(j-1), i, plane) = img(i, j, plane);
            end
        end
    end
end

Answer 1

[Ravi Keshri]

Okay I found a solution.

rotated = uint8(rotated);

rotated was double and needs to be converted to uint8 at the end of the function.

Can anyone please explain me why this happens?