I don't understand something

Question

struct Val {
int nr;
};

void func(Val* v) {
Val* w = v;
w->nr = 10;
}

int main() {
Val* v = new Val;
v->nr = 4;
func(v);
cout << v->nr; //10
}

Why is 10 displayed and not 4?

I mean, I just changed w, not v.

And "v" is not initialized "Val*& v", but it changes.

Answer 1

You are assingned v pointer into w in function. So now w is alias for v. Both are references. So change in one reflect back on other original..
v is initialized Val* v = new Val;