1、构造函数的调用顺序
基类构造函数、对象成员构造函数、派生类本身的构造函数
2、析构函数的调用顺序
派生类本身的析构函数、对象成员析构函数、基类析构函数（与构造顺序正好相反）
3、特例
局部对象，在退出程序块时析构
静态对象，在定义所在文件结束时析构
全局对象，在程序结束时析构
继承对象，先析构派生类，再析构父类
对象成员，先析构类对象，再析构对象成员
4、例子
#include <iostream>
using namespace std;
class Base1
{
public: Base1(void){cnt++;cout<<"Base1::constructor("<<cnt<<")"<<endl;} ~Base1(void){cnt--;cout<<"Base1::deconstructor("<<cnt + 1<<")"<<endl;} private: static int cnt; }; int Base1::cnt = 0; class Base2 { public: Base2(int m){num = m; cout<<"Base2::constructor("<<num<<")"<<endl;} ~Base2(void){cout<<"Base2::deconstructor("<<num<<")"<<endl;} private: int num; }; class Example { public: Example(int n){num = n; cout<<"Example::constructor("<<num<<")"<<endl;} ~Example(void){cout<<"Example::deconstructor("<<num<<")"<<endl;} private: int num; }; class Derived:public Base1, public Base2 { public: Derived(int m, int n):Base2(m),ex(n){cnt++;cout<<"Derived::constructor("<<cnt<<")"<<endl;} ~Derived(void){cnt--;cout<<"Derived::deconstructor("<<cnt+1<<")"<<endl;} private: Example ex; static Example stex; //Example::constructor(1) //不能输出 static int cnt; }; int Derived::cnt = 0; Derived ge_a(1,2); // Base1::constructor(1) // Base2::constructor(1) // Example::constructor(2) // Derived::constructor(1) static Derived gs_b(3,4); // Base1::constructor(2) // Base2::constructor(3) // Example::constructor(4) // Derived::constructor(2) int main(void) { cout << "---------start---------" << endl; Derived d(5,6); // Base1::constructor(3) // Base2::constructor(5) // Example::constructor(6) // Derived::constructor(3) Derived e(7,8); // Base1::constructor(4) // Base2::constructor(7) // Example::constructor(8) // Derived::constructor(4) cout << "----------end----------" << endl; //Derived e(7,8) 析构 // Derived::deconstructor(4) // Example::deconstructor(8) // Base2::deconstructor(7) // Base1::deconstructor(4) //Derived d(5,6) 析构 // Derived::deconstructor(3) // Example::deconstructor(6) // Base2::deconstructor(5) // Base1::deconstructor(3) return 0; } //static Derived gs_b(3,4) 析构 // Derived::deconstructor(2) // Example::deconstructor(4) // Base2::deconstructor(3) // Base1::deconstructor(2) //Derived ge_a(1,2) 析构 // Derived::deconstructor(1) // Example::deconstructor(2) // Base2::deconstructor(1) // Base1::deconstructor(1) //static Example stex 析构 //Example::deconstructor(1) //不能输出
#include <iostream>
using namespace std;
class A
{
public: A(){cout<<"A::constructor"<<endl;}; ~A(){cout<<"A::deconstructor"<<endl;}; }; class B { public: B(){cout<<"B::constructor"<<endl;}; ~B(){cout<<"B::deconstructor"<<endl;}; }; class C : public A { public: C(){cout<<"C::constructor"<<endl;}; ~C(){cout<<"C::deconstructor"<<endl;}; private: // static B b; B b; }; class D : public C { public: D(){cout<<"D::constructor"<<endl;}; ~D(){cout<<"D::deconstructor"<<endl;}; }; int main(void) { C* pd = new D(); delete pd; return 0; } /* Output ----->B b A::constructor B::constructor C::constructor D::constructor C::deconstructor B::deconstructor A::deconstructor ----->static B b A::constructor C::constructor D::constructor C::deconstructor A::deconstructor */
