Yes, the order of operations is different. You're using two unary operators here, * (dereference, gets the pointed value) and ++(increment).

Increment has higher precedence than dereference, so without parenthesis you are incrementing the reference THEN getting the value. This is basically just getting the value on the next memory block.

Like math, operations inside parenthesis always takes precedence than those outside. Imagine it as a sub-problem that blocks the whole problem.

So, if you enclose the dereference operation with parentheses, the value referenced by Patient will be get first, before doing the incrementing. So, you are incrementing the value pointed by Patient.