Folks need explanation for a particular function in c based on prefix operator

Question

int main(){
int x=1;
x= ++x + ++x;
printf("%d",x);
return 0;
}

Answer 1

x = 1
x = ++x + ++x --> 1 = ++1 + ++1

When compiler sees first prefix increment operator
2 = 2 + ++2

When compiler sees the second prefix increment operator
3 = 3 + 3

Now compiler will sum both values and assign it to x
3 = 6 --> x = 6

Answer 2

Unfortunately the structure

x = ++x + ++x;

has undefined behavior in C/C++,

" Modifying an object between two sequence points more than once produces undefined behavior. "
That means even though the precedence of increment/decrement operator is defined but by combining multiple of them in an expression like that, there's no guarantee what the final result can be. Even something like

x = ++x + 1;

is still undefined (Wikipedia example).
Just take a look the result of the x in two different compilers (clang and g++)

https://rextester.com/LJT63493

https://rextester.com/OKAQ48119

_____
https://en.m.wikipedia.org/wiki/Undefined_behavior

Answer 3

nAutAxH AhmAd tq bro

Answer 4

C++ Soldier (Babak) sure