Seconds counter within a day?

Hello,

Please help me with the following:

I need to count the seconds from one period to another within a day.

For example,

the start point would be 00:00:01

and the final point would be (for example)

18:06:00

Thank you.

Best,

Pavlos

Answer 1

[Walter Roberson]

t = datenum('18:06:00') - datenum('00:00:01');
seconds = t * 24 * 60 * 60;