C++多继承下多态内存释放问题

Question

#include <iostream>
#include <string>
using namespace std;

class Animal1
{
public:
    virtual void fun1() = 0;
};
class Animal2
{
public:
    virtual void fun2() = 0;
};

class Cat : public Animal1, public Animal2
{
public:
    virtual void fun1()
    {
        cout << "fun1" << endl;
    }
    virtual void fun2()
    {
        cout << "fun2" << endl;
    }
};

int main(void)
{
    Animal1 *a1 = new Cat;
    Animal2 *a2 = new Cat;    
    a1->fun1(); //fun1
    a2->fun2(); //fun2
    delete a1;
    delete a2;
    return 0;
}

释放指针a2内存的时候直接程序崩溃了，求大神帮助！

Answer 1

#include <iostream>
#include <string>
using namespace std;

class Animal1
{
public:
    virtual void fun1() {}
    //virtual ~Animal1(){}
};
class Animal2
{
public:
    virtual void fun2() {}
    virtual ~Animal2(){}
};

class Cat : public Animal1, public Animal2
{
public:
    virtual void fun1()
    {
        cout << "fun1" << endl;
    }
    virtual void fun2()
    {
        cout << "fun2" << endl;
    }
};

int main(void)
{
    Cat* c = new Cat;
    Animal2* a2 = c;
    delete a2;
    return 0;
}

void __CRTDECL operator delete(void* const block) noexcept
{
    #ifdef _DEBUG
    _free_dbg(block, _UNKNOWN_BLOCK);
    #else
    free(block);
    #endif
}

如果给animal2写了虚析构函数，block和c是相等的，如果没写，block和a2是相等的。