1.cpp

#include <iostream>
using namespace std;

class container {
	friend class vector;
public:
	container() { size = 0; }
	float* p;
	container(int s) :size(s) {}
	int& getsize() { return size; }

protected:
	int size;
};

class vector :public container {

	int call_num;
public:
	explicit vector(int l) :len(l), container(1 * 100) {
		p = new float[size];
	}
	vector(const container& con) :container(1 * 100) {
		
		this->size = size;
		this->p = new float[con.size];
		len = 0;

	}
	int len;
	//len is useless!!
	int& getlen() {
		call_num++;
		return len;
	}
	~vector() = default;
};

int main() {

	container c1(100);
	vector v1 = c1;
	container& r1 = v1;
	container c2 = 100;
	c2.getsize() = 20;
	cout << c2.getsize();
	vector v2 (100);
	v2.getlen() = 40;
	cout << v2.getlen();
}