#include <iostream>

class Base
{
public:
	Base():x_(0),y_(0){}; //インライン関数
	Base(int _x,int _y):x_(_x),y_(_y){};
	int x_;
	int y_;
};
class Extend:public Base
{
public:
	Extend():Base(),z_(0){}
	Extend(int _x,int _y,int _z):Base(_x,_y),z_(_z){}
	int z_;
};

using namespace std;
int main() {
	Extend iExt(2,3,4);
	cout << "(x, y, z) = " << iExt.x_ << ", " << iExt.y_ << ", " << iExt.z_ << endl;
	Base iDown_casted = (Base)iExt; //アップキャスト
	cout << "(x, y, z) = " << iDown_casted.x_ << ", " << iDown_casted.y_ << ", " << iDown_casted.z_ << endl;
}