function timestamp(number)
% TIMESTAMP  prints time in hours:minutes:seconds format, from timestamp
% number (number of seconds after midnight)
    h = floor(number/3600);
    if h < 0
        h = h+24;
    end
    rest = mod(number,3600);
    min = floor(rest/60);
    sec = mod(rest,60);
    sprintf("%d:%d:%d",h,min,sec)
end

