类的嵌套定义、使用以及用头文件实现多个文件编程（匠心之作C++ p105 22 ）

我的方法1：

#include<iostream>

class Point{
    int cX,cY;
public:
    void setPoint(int x,int y){
        cX=x;cY=y;
    }
    int getPointX(){
        return cX;
    }
    int getPointY(){
        return cY;
    }
};
class Circle{
    int cRadius;Point cCenter;
public:
    void setCircle(int radius,Point center){
        cRadius=radius;cCenter=center;
    }
    int getRadius(){
        return cRadius;
    }
    int getCenterX(){
        return cCenter.getPointX();
    }
    int getCenterY(){
        return cCenter.getPointY();
    }
};
int main(){
    Point p1,cp;Circle c1;
    p1.setPoint(7,0);cp.setPoint(0,0);
    c1.setCircle(8,cp);
    if((c1.getCenterX()-p1.getPointX())*(c1.getCenterX()-p1.getPointX())+
        (c1.getCenterY()-p1.getPointY())*(c1.getCenterY()-p1.getPointY())>
        c1.getRadius()*c1.getRadius())
        std::cout<<"点在圆外
"<<std::endl;
    else if(((c1.getCenterX()-p1.getPointX())*(c1.getCenterX()-p1.getPointX())+
        (c1.getCenterY()-p1.getPointY())*(c1.getCenterY()-p1.getPointY())==
        c1.getRadius()*c1.getRadius()))
        std::cout<<"点在圆上
"<<std::endl;
    else
        std::cout<<"点在圆内
"<<std::endl;
    system("pause");
    return 0;
}

 老师的做法：

#include<iostream>
class Point{
    int cX,cY;
public:
    void setPoint(int x,int y){
        cX=x;cY=y;
    }
    int getPointX(){
        return cX;
    }
    int getPointY(){
        return cY;
    }
};
class Circle{
    int cRadius;Point cCenter;
public:
    void setCircle(int radius,Point center){
        cRadius=radius;cCenter=center;
    }
    int getRadius(){
        return cRadius;
    }
    Point getCenter(){
        return cCenter;
    }
};
int main(){
    Point p1,cp;//声明2个点，p1是任意点，cp是圆心
    Circle c1; //声明圆
    p1.setPoint(0,5); //赋值点
    cp.setPoint(0,0); //赋值圆心
    c1.setCircle(6,cp); //设置圆的半径及圆心

    if((c1.getCenter().getPointX()-p1.getPointX())*
        (c1.getCenter().getPointX()-p1.getPointX())+
        (c1.getCenter().getPointY()-p1.getPointY())*
        (c1.getCenter().getPointY()-p1.getPointY())>
        c1.getRadius()*c1.getRadius())
        std::cout<<"点在圆外

";
    else if((c1.getCenter().getPointX()-p1.getPointX())*
        (c1.getCenter().getPointX()-p1.getPointX())+
        (c1.getCenter().getPointY()-p1.getPointY())*
        (c1.getCenter().getPointY()-p1.getPointY())==
        c1.getRadius()*c1.getRadius())
        std::cout<<"点在圆上

";
    else
        std::cout<<"点在圆内

";
    system("pause");
    return 0;
}

 多文件实现方法，point.h:

#pragma once
#include<iostream>
class Point{
public:
    int cX,cY;
public:
    void setPoint(int x,int y);
    int getPointX();
    int getPointY();
};

circle.h:

#pragma once
#include<iostream>
#include"point.h"
class Circle{
    int cRadius;Point cCenter;
public:
    void setCircle(int radius,Point center);
    int getRadius();
    Point getCenter();
};

point.cpp

#include "point.h"
void Point::setPoint(int x,int y){
    cX=x;cY=y;
}
int Point::getPointX(){
    return cX;
}
int Point::getPointY(){
    return cY;
}

circle.cpp

#include"circle.h"

void Circle::setCircle(int radius,Point center){
    cRadius=radius;cCenter=center;
}
int Circle::getRadius(){
    return cRadius;
}
Point Circle::getCenter(){
    return cCenter;
}

主函数circle3.cpp：

#include<iostream>
#include"circle.h"
#include"point.h"
int main(){
    Point p1,cp;//声明2个点，p1是任意点，cp是圆心
    Circle c1; //声明圆
    p1.setPoint(0,9); //赋值点
    cp.setPoint(0,0); //赋值圆心
    c1.setCircle(6,cp); //设置圆的半径及圆心
    int distance=(c1.getCenter().getPointX()-p1.getPointX())*
        (c1.getCenter().getPointX()-p1.getPointX())+
        (c1.getCenter().getPointY()-p1.getPointY())*
        (c1.getCenter().getPointY()-p1.getPointY());

    if(distance>c1.getRadius()*c1.getRadius())
        std::cout<<"点在圆外

";
    else if(distance==c1.getRadius()*c1.getRadius())
        std::cout<<"点在圆上

";
    else
        std::cout<<"点在圆内

";
    system("pause");
    return 0;
}