C++类成员对象析构问题

当执行delete c时，析构Test 时(delete p)会出现问题。原因在哪里??
解决方案

代码块

#include <iostream>
using namespace std;

class Test
{
public:
    Test()
    {

    }
    ~Test()
    {
        cout<<"Test destructor"<<endl;
        if(p!=NULL)
        delete p;
    }
private :
    int *p;
};

class Test1
{
public:
    Test1()
    {

    }
    ~Test1()
    {
        cout<<"Test1 destructor"<<endl;
    }
};

class Test2
{
public:
    Test2()
    {

    }
    ~Test2()
    {
        cout<<"Test2 destructor"<<endl;
    }
private:
    Test a;
    Test1 b;
};

int main()
{
    Test2 *c=new Test2;
    delete c;
    //system("pause");
    return 0;
}