hình chữ nhật class

#include<iostream>
using namespace std;
class hinhchunhat {
public :
	hinhchunhat();
	void set_cach(int, int);
	void get_canh();
	void dientich(int, int);

private :
	int chieudai;
	int chieurong;
};
class hinhhop: public hinhchunhat {
private:
	int chieucao;
	int chieurong;
	int chieudai;
public:
	hinhhop();
	void set_chieucao(int);
	void get_chieucao();
	void thetich(int, int, int);
};
hinhhop::hinhhop(){
	chieudai = 0;
	chieurong = 0;
	chieucao = 0;

}
void hinhhop::set_chieucao(int chieucao) {
	this->chieucao = chieucao;
}
void hinhhop::get_chieucao() {
	cout << "chieu cao : " << chieucao;
}
void hinhhop::thetich(int chieudai, int chieurong, int chieucao) {
	cout << "thetich :" << chieudai*chieurong*chieucao;
}
hinhchunhat::hinhchunhat() {
	chieudai = 0;
	chieurong = 0;
}
void hinhchunhat::set_cach(int chieudai, int chieurong) {
	this->chieudai = chieudai;
	this->chieurong = chieurong;
}
void hinhchunhat::get_canh() {
	cout << chieudai << " " << chieurong;
}
void hinhchunhat::dientich(int chieudai, int chieurong) {
	cout << "dientich :" << chieudai*chieurong;
}

void main() {
	hinhchunhat a;
	hinhhop b;
	a.set_cach(4, 6);
	a.get_canh();
	a.dientich(5, 7);
	b.set_cach(4, 5);
	b.set_chieucao(6);
	b.get_canh
	b.thetich(6, 7, 8);

	system("pause");
}