运行代码，进入调试模式，分析对象的构造函数和析构函数调用时机，代码如下： #include <iostream> using namespace std; class Base1 { protected: int data1; public: Base1(int a=8) { data1 = a; cout<<data1<<", Base1 Constructor\n"; } ~Base1( ) { cout<<data1<<", Base1 Destructor\n"; } }; class Base2 { protected: int data2; public: Base2(int a=9) { data2 = a; cout<<data2<<", Base2 Constructor\n"; } ~Base2( ) { cout<<data2<<", Base2 Destructor\n"; } }; class Derived:public Base1, public Base2 { int d; public: Derived(int x, int y, int z) : Base1(x), Base2(y) //A { d=z; cout<<"Derived Constructor\n"; } ~Derived( ) { cout<<"Derived Destructor\n"; } void Show( ) { cout<<data1<<','<<data2<<','<<d<<endl; } }; int main( ) { Derived c(1, 2, 3); c.Show( ); return 0; }先分析结果然后如果将A行代码替换为 Derived(int x,int y,int z)，分析程序结果

程序的输出结果是：

1, Base1 Constructor
2, Base2 Constructor
Derived Constructor
1,2,3
Derived Destructor
2, Base2 Destructor
1, Base1 Destructor

如果将A行代码替换为`Derived(int x,int y,int z)`，输出结果不会有变化，因为这是派生类的构造函数，会自动调用基类的构造函数。