Есть ли тут UB ?

#include <iostream>
 
using namespace std;
 
class A
{
public:
    A() { std::cout << "Adef" << std::endl; x = 4; }
    A(const A& _a) { std::cout << "cA&" << std::endl; x = 7; }
    unsigned x;
};
 
class B : public A
{
public:
    unsigned y;
    B()
    {std::cout << "Bdef" << std::endl; x = 3; y = 8; }
    B(const B& _b)
    { std::cout << "cB&" << std::endl; x = 7; }
    B& operator =(const B&)
    { std::cout << "B=&" << std::endl; x = 7; return *this; }
    int foo() const volatile { std::cout << "foo" << std::endl; return 555; }
};
 
int main()
{
    using std::cout;
    using std::endl;
    cout << "-----------" << endl;
    // class B : public A
    A * pa = new A; 
    A & ra = *pa;
    cout << "-----------" << endl;
    B & rb = static_cast<B&>(ra);
    rb.foo();
    rb.y = 55;
    cout << "-----------" << endl;
    return 0;
}

T *ptr_t(some_adress);

*ptr_t = some_val_t;

#include <iostream>
using namespace std;
struct B1
{
    int a1[10];
};
struct B2
{
    int a2[10];
};
 
struct D12 : public B1, public B2
{};
 
struct D21 : public B2, public B1
{};
 
struct D1 : public B1
{};
 
int main()
{
    D12 d12;
    B1 &b1_d12 = d12;
    B2 &b2_d12 = d12;
    cout<<"&b1_d12 vs &b2_d12 "<<&b1_d12<<' '<<&b2_d12<<endl;
 
    D21 d21;
    B1 &b1_d21 = d21;
    B2 &b2_d21 = d21;
    cout<<"&b1_d21 vs &b2_d21 "<<&b1_d21<<' '<<&b2_d21<<endl;
 
    //and
    D1 d1;
    B1 &b1=d1;
    cout<<"&b1 vs &d1 "<<&b1<<' '<<&d1<<endl;
 
return 0;
}

#include <iostream>
 
struct B
{
  int i;
};
 
struct D : B
{
  int j;
  virtual ~D() {}
};
 
int main()
{
  D d;
  std::cout << &d << " " << (B *) &d << std::endl;
}