function [td] = timediff(t1,t2)
% t1 is [h m s]
% t2 is [h m s]

t1 = t1(:)';
t2 = t2(:)';

t1sec = hms2sec(t1);
t2sec = hms2sec(t2);

tdsec = t2sec-t1sec;

[td,sgn] = sec2hms(tdsec);

tdd = abs(td);

disp(['t1   = ' num2str(t1(1)) ' h ' num2str(t1(2)) ' m ' num2str(t1(3)) 's'])
disp(['t2   = ' num2str(t2(1)) ' h ' num2str(t2(2)) ' m ' num2str(t2(3)) 's'])
if sgn == 1
    disp(['diff = ' num2str(tdd(1)) ' h ' num2str(tdd(2)) ' m ' num2str(tdd(3)) 's  t2 later than t1'])
else
    disp(['diff = ' num2str(tdd(1)) ' h ' num2str(tdd(2)) ' m ' num2str(tdd(3)) 's  t2 earlier than t1'])
end

function [t,sgn] = sec2hms(tsec)
sgn = sign(tsec);
if sgn == -1
    tsec = -tsec;
end

th = fix(tsec/3600);
tms = rem(tsec,3600);
tm = fix(tms/60);
ts = rem(tms,60);

t = [th tm ts];

if sgn == -1
    t = -t;
end


function [tsec]= hms2sec(t)
tsec = 3600*t(1) + 60*t(2) +t(3);