#include
#include

class?Triangle
{
public:
	friend?Triangle?operator?+?（const?Triangle&?t1const?Triangle&?t2）;
	Triangle（double?t_lengthdouble?t_widthdouble?t_high）;
????Triangle（）;
	void?area（）;
	void?input（）;
	void?output（）;
private:
	double?length;
	double?width;
	double?high;
	double?areas;
};
int?main（）
{
	Triangle?tri（000）tri1;
	tri.area（）;
	int?answer;
	do
	{
		cout<	????tri1.input（）;
	????tri1.area（）;
		tri=tri1+tri;
		cout?<		cin?>>?answer;
	}while（answer!=0）;
	cout?<	tri.output（）;
????return