C++中用父类对象初始化子类的构造函数是怎么回事

Answer 1

#include <iostream>
using namespace std;
 
class father
{
public:
    father(father& c)
        :x(c.x),y(c.y){}
private:
    int x;
    int y;
};
 
class son
{
public:
    son(father& c)
        :father(c),z(0){}
 
private:
    int z;
};