function contrast(file)
image = imread(file);
[rows, cols] = size(image);
large = max(max(image));
small = min(min(image));
rangeOriginal = large - small;

for i = 1:rows
    for j = 1:cols
        image(i,j) = image(i,j) / rangeOriginal * 255;
        
    end
end

imwrite(image, 'contrastOut.pgm', 'pgm');

end