阅读程序，写出程序的运行结果并理解其运行机制。

#include 
     
      using namespace std;class A{public:    A(){
    cout<<"A";}    ~A(){
    cout<<"~A";}};class B{    A *p;public:    B()    {        cout<<"B";        p=new A();    }    ~B()    {        cout<<"~B";        delete p;    }};int main(){    B obj;    return 0;}
     

(2)

#include 
     
      using namespace std;class MyClass{public:    MyClass(int x=0):i(x){
    cout<<"C"<
      
       SetValue(p[i]->GetVal()*2);    }    for (i=0; i<3; i++)        delete p[i];    cout<
      
     

(3)

#include 
     
      using namespace std;class AA{public:    AA(int i,int j)     {        A=i;        B=j;        cout<<"Constructor\n";    }    AA(AA &obj)     {        A=obj.A+1;        B=obj.B+2;        cout<<"Copy_Constructor\n";    }    ~AA() {        cout<<"Destructor\n";    }    void print()    {        cout<<"A="<
      <<",B="<<
        
         print();    delete pa;    return 0;}