为什么下面的代码没有崩溃，尽管我已经删除了对象?

class object
{
  public:
    void check()
    {
      std::cout<<"I am doing ok..."<<std::endl;
    }
};

int main()
{
  object *p = new object;
  p->check();
  delete p;
  p->check();
  delete p;
  p->check();
}
class object
{
  public:
    void check()
    {