Different results of compilers in c++ code. [Solved]

Question

int b= 7;
cout<< (++b + b++);

why the answer is 17 and not 16?, I was checking in many compilers, some gave 16

Answer 1

correct answer is 16,
its all about pre increment and post increment.

Answer 2

that's right Meraj according to the definition, ++b = 8, b++ = 8, thus, the answer is 16, but the majority compilers to gave 17