C++ output - Who does explain me?

Question

Why final values of b is 300, whilst a remains 200? It's like p=q assignment is left-to-right!

#include <iostream>
using namespace std;

int main() {
int a = 200, b = 100;
int *p = &a, *q = &b;
p = q;
*p = 300;
cout << b << a;
return 0;
}

Answer 1

Because of line
p = q
p points to b too. That means that *p = 300 alters b, not a.

Answer 2

Tricky! Just take a breath and read the code..

*q=&b // pointer q is initialized with &b
p=q // the address value in q(which is &b) is assigned to p
Now p contains &b
*p =300 // 300 is assigned to b trough p pointer.

Answer 3

When p=q was coded, p started pointing to b and then value was substituted in case of p. So tht means we changed b's value.