C++基类构造器的自动调用

虽然基类的构造器和解构器不会被派生类继承，但它们会被派生类的构造器和解构器自动调用，今天我们用代码实证一下。

验证代码

源代码，仔细看注释内容：
D:\YcjWork\CppTour>vim c2004.cpp

#include <iostream>using namespace std;
/*** 基类不同构造器的调用
*/
class Mother{
public:Mother(){cout << "Mother: no param" << endl;}Mother(int a){cout << "Mother: int param" << endl;}~Mother(){cout << "Deconstruction Mother" << "\n\n";}
};
class Daughter: public Mother{
public:Daughter(int a){ //派生类构造器调用基类的默认构造器Mother()cout << "Daughter: int param" << "\n\n";}~Daughter(){cout << "Deconstruction Daughter" << "\n";}
};
class Son: public Mother{
public:Son(int a): Mother(a){ //派生类构造器调用基类的指定构造器Mother(int a)cout << "Son: int param" << "\n\n";}~Son(){cout << "Deconstruction Son" << "\n";}
};int main(){{Daughter mary(5);}{Son jack(6);}return 0;
}

编译运行

构造器的调用顺序：
先构造基类，再构造派生类

解构器的调用顺序：
先派生类解构，再基类解构

D:\YcjWork\CppTour>gpp c2004D:\YcjWork\CppTour>g++ c2004.cpp -o c2004.exeD:\YcjWork\CppTour>c2004
Mother: no param
Daughter: int paramDeconstruction Daughter
Deconstruction MotherMother: int param
Son: int paramDeconstruction Son
Deconstruction MotherD:\YcjWork\CppTour>

运行截屏
C++基类构造器的自动调用