# 用c++设计一个类Line，用于表示二维坐标体系中的任意一条直线并输出该直线的属性。

``````#include
#include
using namespace std;
class Line
{
private:
double x1,y1;
double x2,y2;
double k,b;
public:
Line();
Line(double m_x1,double m_y1,double m_x2,double m_y2):x1(m_x1),y1(m_y1),x2(m_x2),y2(m_y2){}
~Line(){};
void equation();   //方程
void point();    //交点
void slope();   //斜率
};
Line::Line()
{
x1=0,y1=0;
x2=0,y2=0;
k=0,b=0;
}
void Line::equation()
{
if(x2==x1)
cout<<"该直线方程是：x="<<x1<<endl;
else
{

b=y1-x1*k;      //直线方程与y轴的交点
cout<<"该直线方程是：y="<<k<<"x+"<<b<<endl;
}
}
void Line::point()
{
if(x2==x1)
cout<<"该直线方程只与x轴有的交点：("<<x1<<",0)"<<endl;
else if(y1==y2)
cout<<"该直线方程只与y轴有的交点：(0,"<<b<<")"<<endl;
else
{
cout<<"该直线方程与x轴的交点：("<<(-b/k)<<",0)"<<endl;
cout<<"该直线方程与y轴的交点：(0,"<<b<<")"<<endl;
}
}
void Line::slope()
{
if(x2==x1)
cout<<"该直线的斜率是无穷大"<<endl;
else
{
k=(y2-y1)/(x2-x1);          //求斜率
cout<<"该直线的斜率是："<<k<<endl;
}
}

void main()
{
double x1,x2,y1,y2;
cout<<"请输入任意两个坐标：";
cin>>x1>>y1>>x2>>y2;
if(x1==y1==x2==y2)
{
cout<<"请重新输入任意两个坐标：";
cin>>x1>>y1>>x2>>y2;
}
Line a(x1,y1,x2,y2);
a.slope();      //输出直线斜率
a.equation();   //输出直线方程
a.point();      //输出直线与x、y轴的交点
}
``````