完成C++第9章的作业

    #include<iostream>
    #include<cmath>
    #include<iomanip> 
    class Beeline{
    	private:
    		int x1;
    		int x2;
    		int y1;
    		int y2;
    	public:
    		Beeline(int xx1=0,int yy1=0,int xx2=0,int yy2=0):x1(xx1),y1(yy1),x2(xx2),y2(yy2){}; 
    		float length();
    		void show();
    };
    float Beeline::length()
    {
    	return (sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
    }
    void Beeline::show()
    {
    	std::cout << "(" << x1 << ", " << y1 << "),(" << x2 <<", " << y2 <<")" << std::endl;
    }