In Complexity Analysis why is ++ considered to be 2 operations?

Question

In my Computer Science II class, the professor considers ++,--,*=, etc. to be 2 operations. However, at the Assembly level this is not really two operations. Can someone explain or is this just for the sake of simplicity?

Answer 1

I'd actually consider it to be 3 operations: read, increment (or whatever), write. That's assuming it's reading from some sort of shared memory into some sort of local storage (e.g. register or stack), operating on the local storage, then writing back.

How many operations it is at assembly level will depend on what you're incrementing, the platform, the hardware etc.