一个循环引用的例子

#include <iostream>
using namespace std;

class B;

class A
{
public:
    ~A() { cout <<"destroying A\n"; }
public:
    B *abp;
};

class B
{
public:
    ~B() { cout <<"destroying B\n"; }

public:
    A *bap;
};

void test()
{
    A *ap = new A();
    B *bp = new B();

    ap->abp = bp;
    bp->bap = ap;
}

int main()
{
    cout<<"begin test...\n";
    test();
    cout<<"end test.\n";
    system("PAUSE");
    return 0;
}