Why does this code give the input "10"?

Question

#include <iostream>
using namespace std;

int main() {
int a, b;
a=4;
b=a + ++a;
cout<<b;
return 0;
}

Answer 1

a + ++a is equal to a + (a=1+a).
since a was incremented, that means its new value is 5. so 5+5.

it takes the incremented value as new value during the operation because we put the plus sign(increment operator) before the number.

Answer 2

He's right, the output should be 10 because a in this case was changed during the operation to 5 with the ++a. The answer would have been 9 if b was presented as b=a+a++; because the entire line is calculated first in c++ unlike java
https://code.sololearn.com/cDOlE0rgTSPf/?ref=app