How to determine the output of this code?

Question

int a = 5
cout<< a++ + ++a

Answer 1

First, a copy of a is made, using the postfix notation. We have 5 to work with.
Increment a. Now a = 6 but we are working with the old copy of a so...
Value 5 is used as the first argument of operator+ function.
Then we increment a(the incremented one, with value of 6), so now a is 7.

Now we have the two needed arguments of the operator+ function, the old copy of a we made(with value of 5) and the newly incremented a(with value of 7)

The expression that is being evaluated is 5+7 so the output should be 12.