目的:
//只执行了 父类的析构函数
//向通过父类指针 把 所有的子类对象的析构函数 都执行一遍
//向通过父类指针 释放所有的子类资源
方法:在父类的析构函数前+virtual关键字
#define _CRT_SECURE_NO_WARNINGS #include <iostream> using namespace std; //虚析构函数 class A { public: A() { p = new char[20]; strcpy(p, "obja"); printf("A()\n"); } virtual ~A() { delete [] p; printf("~A()\n"); } protected: private: char *p; }; class B : public A { public: B() { p = new char[20]; strcpy(p, "objb"); printf("B()\n"); } ~B() { delete [] p; printf("~B()\n"); } protected: private: char *p; }; class C : public B { public: C() { p = new char[20]; strcpy(p, "objc"); printf("C()\n"); } ~C() { delete [] p; printf("~C()\n"); } protected: private: char *p; }; void howtodelete(A *base) { delete base; //这句话不会表现成多态 这种属性 } void main() { C *myC = new C; //new delete匹配 // delete myC; //直接通过子类对象释放资源 不需要写virtual (即不使用虚析构) //howtodelete(myC); //使用父类对象释放资源,使用虚析构 cout<<"hello..."<<endl; system("pause"); return ; }