% 解答:
% (1)
start_date = datenum('2023-04-01');
end_date = datenum('2023-12-25');
weight_difference = 100 - 85;
days_difference = end_date - start_date;
average_weight_loss = weight_difference / days_difference;
% (2)
formatOut1 = 'mmm.dd,yyyy';
formatOut2 = 'yyyy/mm/dd';
start_date_str1 = datestr(start_date, formatOut1);
end_date_str1 = datestr(end_date, formatOut1);
start_date_str2 = datestr(start_date, formatOut2);
end_date_str2 = datestr(end_date, formatOut2);
fprintf('[%s]到[%s]共%d天,平均每天减少%.2fkg.\n', start_date_str1, end_date_str1, days_difference, average_weight_loss);
fprintf('[%s]到[%s]共%d天,平均每天减少%.2fkg.\n', start_date_str2, end_date_str2, days_difference, average_weight_loss);