Can I get the total # of posts in have_posts()? Need to test if on last post.

I’m creating a horizontal layout where posts are side by side instead of stacked vertically on top of each other.

To close a table row with </tr> tags I need to find out if the current post being processed in the loop is the last post.

Is there a way to test if have_posts() is outputting the last post?

Thanks,
DAN