Question

华侨大学面向对象编程期末考试题求解析

阅读以下程序并给出执行结果
#include <iostream>
using namespace std;
class Base
{
protected:
int b;
public:
Base(int bval=0)
{ cout<<"Constructing Base..."<<bval<<endl;
b=bval;
}
};
class Derive1: virtual public Base
{
protected:
int d1;
public:
Derive1(int bval, int dval):Base(bval)
{ cout<<"Constructing Derive1..."<<dval<<endl;
d1=dval;
}
};
class Derive2:virtual public Base
{
protected:
int d2;
public:
Derive2(int bval,int dval):Base(bval)
{ cout<<"Constructing Derive2..."<<dval<<endl;
d2=dval;
}
};
class Derive:public Derive1, public Derive2
{ protected:
int d;
public:
Derive(int bval, int dval1,int dval2,int dval);
};
Derive::Derive(int bval, int dval1,int dval2,int dval)
:Derive1(bval, dval1),Derive2(bval, dval2),Base(bval)
{
cout<<"Constructing Derive..."<<dval<<endl;
d=dval;
}
void main()
{
Derive Objectd(1,2,3,4);
}
答案：Constructing Base... 1
Constructing Derive1... 2
Constructing Derive2... 3
Constructing Derive... 4
请求高手或者有心得的人给下详细解析谢谢大家

Answer 1

还真有点难度 想了一会儿
构造的时候的顺序是 父类到子类
所以先是Constructing Base
然后由于Derive1，Derive2是虚继承
所以构造Derive1，Derive2时不会构造Base
最后才是Derive的构造函数