第十二周项目四 点与圆的关系

问题及代码

/*    ALL rights reserved.                           *文件名称: 初学对象12                       作者：李长鸿                        *完成时间：2015.5.27                 *问题描述： 点与圆的继承   */  #include <iostream>#include<Cmath>using namespace std;class Point{    double x,y;public:    Point(double a=0,double b=0):x(a),y(b) {}    void setp()    {        cout<<"请输入点的坐标：";        char a,b,c;        cin>>a>>x>>b>>y>>c;        while(a!='('||b!=','||c!=')')        {            cout<<"输入有误，请再次输入：";            cin>>a>>x>>b>>y>>c;        }    }    inline double getx()    {        return x;    }    inline double gety()    {        return y;    }    void printp()    {        cout<<"("<<x<<","<<y<<"); ";    }};class Circle:public Point{    double r;public:    Circle(double a=0,double b=0,double c=1):Point(a,b),r(c) {}    inline double getr()    {        return r;    }    friend istream &operator>>(istream&in,Circle&c);    friend ostream &operator<<(ostream&out,Circle&c);    double area();};istream &operator>>(istream &in,Circle &c){    c.setp();    cout<<"请输入半径：";    in>>c.r;    while(c.r<=0)    {        in>>c.r;    }    return in;}double Circle::area(){    return 3.14*r*r;}ostream& operator<<(ostream &out,Circle &c){    cout<<"圆心坐标为:";    c.printp();    cout<<"半径为:"<<c.r<<"; ";    cout<<"面积为:"<<c.area();    return out;}int locate(Point p,Circle c){    double h=sqrt((p.getx()-c.getx())*(p.getx()-c.getx())+(p.gety()-c.gety())*(p.gety()-c.gety()));    if(h==c.getr())        return 0;    if(h<c.getr())        return -1;    if(h>c.gety())        return 1;}int main(){    Circle c1(7,7,7);    Point p1(7,7);    cout<<"p1=";    p1.printp();    cout<<endl;    cout<<"圆为：";    cout<<c1;    cout<<endl;    p1.setp();    cin>>c1;    cout<<c1;    cout<<endl;    cout<<"点";    p1.printp();    cout<<"在";    cout<<c1;    cout<<"的圆";    if(locate(p1,c1)==0)    {        cout<<"上"<<endl;    }    if(locate(p1,c1)>0)    {        cout<<"外"<<endl;    }    if(locate(p1,c1)<0)    {        cout<<"内"<<endl;    }    return 0;}

总结：写<<   >>的重载时，格式的小细节未注意好，operator前的&忘了，out ,  in前的&也忘了，结果系统就给来个内存什么的问题。唉