C++求三角形面积问题

Question

计算三角形周长。定义一个Triangle类来描述三角形，并使用点Point类的对象来表示端点。
在Triangle类构造函数中实现计算周长的功能

Answer 1

#include<iostream>
#include<cmath>
using namespace std;
//点类
class Point
{
private:
double x;
double y;
public:
void set_point(double dx,double dy); //设置点的坐标值
double get_point_x(); //获取点的横坐标值
double get_point_y(); //获取点的纵坐标值
};
//三角形类
class Triangle
{
private:
Point T_point_a;
Point T_point_b;
Point T_point_c;
public:
Triangle(Point pa,Point pb,Point pc)//构造函数
{
T_point_a=pa;
T_point_b=pb;
T_point_c=pc;
}
double get_distance(Point point_a,Point point_b); //求两个点之间的距离
double get_length(); //求三角形的周长
};
void Point::set_point(double dx,double dy)
{
x=dx;
y=dy;
}
double Point::get_point_x()
{
return x;
}
double Point::get_point_y()
{
return y;
}
double Triangle::get_distance(Point point_a,Point point_b)
{
return sqrt((point_a.get_point_x()-point_b.get_point_x())*(point_a.get_point_x()-point_b.get_point_x())+(point_a.get_point_y()-point_b.get_point_y())*(point_a.get_point_y()-point_b.get_point_y()));
}

double Triangle::get_length()
{
return get_distance(T_point_a,T_point_b)+get_distance(T_point_a,T_point_c)+get_distance(T_point_b,T_point_c);
}
int main()
{
Point pa,pb,pc;
double x,y;
cout<<"输入第一个点的坐标："<<endl;
cin>>x>>y;
pa.set_point(x,y);
cout<<"输入第二个点的坐标："<<endl;
cin>>x>>y;
pb.set_point(x,y);
cout<<"输入第三个点的坐标："<<endl;
cin>>x>>y;
pc.set_point(x,y);
Triangle triangle=Triangle(pa,pb,pc);
bool Is_triangle=(triangle.get_distance(pa,pb)+triangle.get_distance(pa,pc)>triangle.get_distance(pb,pc))&&(triangle.get_distance(pa,pb)+triangle.get_distance(pb,pc)>triangle.get_distance(pa,pc))&&(triangle.get_distance(pb,pc)+triangle.get_distance(pa,pc)>triangle.get_distance(pa,pb));
if(!Is_triangle)
cout<<"您输入的坐标不能构成三角形！"<<endl;
else
cout<<"三角形的周长:"<<triangle.get_length()<<endl;
return 0;
}

Answer 2

构造函数不要做其他事情，只负责初始化类成员，明白不？