急！C++补充下面的程序，实现一个三角形类，可以计算三角形面积和周长？

完整的C++程序：

#include <iostream>

#include <math.h>

#include<iomanip>

using namespace std

class Triangle {

public:

Triangle(double x1, double y1, double x2, double y2, double x3, double y3)

double getArea()

double getPerimeter()

private:

double _x1

double _y1

double _x2

double _y2

double _x3

double _y3

double _l1

double _l2

double _l3

}

//在下面的空格实现Triangle类的成员函数

Triangle::Triangle(double x1, double y1, double x2, double y2, double x3, double y3)

{

this->_x1 = x1

this->_y1 = y1

this->_x2 = x2

this->_y2 = y2

this->_x3 = x3

this->_y3 = y3

this->_l1 = sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2))

this->_l2 = sqrt(pow(x3 - x2, 2) + pow(y3 - y2, 2))

this->_l3 = sqrt(pow(x1 - x3, 2) + pow(y1 - y3, 2))

}

double Triangle::getArea()

{

double p = (_l1 + _l2 + _l3) / 2

return sqrt(p * (p - _l1) * (p - _l2) * (p - _l3))

}

double Triangle::getPerimeter()

{

return _l1 + _l2 + _l3

}

int main()

{

double x1, x2, x3, y1, y2, y3

cin >>x1>>y1>>x2>>y2>>x3>>y3

Triangle t(x1, y1, x2, y2, x3, y3)

//在下面的空格按题目要求输出结果

cout <<setiosflags(ios::fixed)<<setprecision(2)<<t.getArea()<<endl

cout <<setiosflags(ios::fixed)<<setprecision(2)<<t.getPerimeter()<<endl

return 0

}

运行测试：

就是说只用写几个函数就可以了对吧！建议看我给我好评哦，亲！

//声明

Rectangle(double x1,double y1,double x2,double y2)

Rectangle&operator=(const Rectangle&obj)

int GetLength()

int GetArea()

//实现

Rectangle::Rectangle(double x1,double y1,double x2,double y2) : _x1(x1),_y1(y1),_x2(x2),_y2(y2){

_width = x2 - x1

_height = y2-y1

}

Rectangle&operator=(const Rectangle&obj){

this._x1 = obj._x1

this._y1 = obj._y1

this._x2 = obj._x2

this._y2 = obj._y2

this._width = obj._width

this._height = obj._height

}

double Rectangle::GetLength(){ return 2*(_width + _height) }

double Rectangle::GetArea(){ return _width * _height }

//使用

cout<<fixed<<setprecision(2) <<r1.GetLength() <<endl <<r1.GetArea()<<endl

<<r1.GetLength() + r2.GetLength() <<endl

<< r1.GetArea() + r2.GetArea() <<endl

因为一个字符数组，必须包含'\n'的部分，你定义了长度为8的，最多输入7个字符，如果输入8个字符‘\n’就没了，但是还是可以俺你的要求输出，可是如果更多的话就不对了。你可以把那个长度改长点，求采纳

---