Do not pay attention to things at ordinary times

++ I

Faster, but it has little impact on Int built-in types.

Let's take a look at the C ++ operator reload chapter.

Front ++ returns the reference of the current object, and returns only an address, very fast

The back-end ++ returns a backup of the original object and calls the secondary copy constructor and the secondary destructor, even if

When RVO is used to optimize the return value, it also needs to be constructed and analyzed at a time. Therefore, when the class is complex, the overhead is very high.

Do not pay attention to things at ordinary times