Can you have a triple minus signs in C programming? What does it mean?

Possible Duplicate:
Why doesn’t a+++++b work in C?

I got this from page 113 on the "An Embedded Software Primer" by David Simon.

I saw this statement below:

iHoursTemp = iHoursTemp + iZoneNew ---iZoneOld;

Can you really have three minus signs in this line? What does a triple minus sign mean?

I believe it is a C programming statement.