Search:

http://msdn.microsoft.com/en-us/library/126fe14k(v=VS.80).aspx
http://www.cppreference.com/operator_precedence.html

As laserlight said, they're evaluated left to right. I'm not a big believer in superfluous parenthesis, but they won't do any harm I guess.

As to the rounding, his result is a double, so casting...

percent[j] = votes[j]/ total * 100;

That will always be zero. Try
percent[j] = votes[j] * 100 / total;

If total is always zero in the loop, use the debugger to look at the values in votes.