#include<iostream> using namespace std; class Point { protected: int x, y; public: Point(int a, int b) { x = a; y = b; } int getX() { return x; } int gerY() { return y; } }; class Circle :public Point { protected: int radius; public: Circle(int a = 0, int b = 0, int r = 0) { radius = r; } int getRadius() { return radius; } }; void main() { Circle c(100, 150, 200); cout << "x=" << c.getX() << ",y=" << c.getY() << ",radius" << c.getRadius() << endl; }

这是一个简单的 C++ 程序，它定义了一个基类 Point 和一个派生类 Circle，Circle 继承自 Point。Point 类表示平面上的一个点，包含 x 和 y 坐标；Circle 类表示平面上的一个圆，它除了继承 Point 类的 x 和 y 坐标外，还包含一个半径 radius。

程序的主函数中创建了一个 Circle 对象 c，并输出它的 x、y 坐标和半径 radius。注意程序中有一个拼写错误，gerY 应该是 getY。

相关问题

#include <iostream> using namespace std; class Point{ public: Point(int x1); int getx() { return x; } protected: int x; }; Point::Point(int x1) { x=x1; cout<<"执行基类的构造函数"<<endl; } class Circle:public Point{ public: Circle(int x1,int y1); int gety() { return y; } protected: int y; }; Circle::Circle(int x1,int y1):Point(x1) { y=y1; cout<<"执行派生类的构造函数"<<endl; } int main() { Circle c(2,1); cout<<"x="<<c.getx<<endl; cout<<"y="<<c.gety<<endl; return 0; }

在 `main` 函数中调用 `getx` 函数时，应该加上括号，即 `c.getx()`，而不是 `c.getx`。请修改以下代码：

#include <iostream>  

using namespace std; 

class Point{
public:
    Point(int x1);
    int getx()
    {
        return x;
    }
protected:
    int x;
};

Point::Point(int x1) {
    x=x1;
    cout<<"执行基类的构造函数"<<endl;
}

class Circle:public Point{
public:
    Circle(int x1,int y1);
    int gety()
    {
        return y;
    }
protected:
    int y;
};

Circle::Circle(int x1,int y1):Point(x1) {
    y=y1;
    cout<<"执行派生类的构造函数"<<endl;
}

int main() {
    Circle c(2,1);
    cout<<"x="<<c.getx()<<endl; //注意这里调用 getx 函数时要加上括号
    cout<<"y="<<c.gety()<<endl;
    return 0;
}

在POINT.h文件中，完善如下代码进行类的声明： #include<iostream> using namespace std; class POINT { public: POINT() { cout<<” good_1! Default constructor of POINT called!” <<endl;} POINT(int xx=0, int yy=0) { x = xx; y = yy; cout<<” good_2! constructor of POINT called!” <<endl;} POINT(POINT& p); virtual ~POINT(){cout<<”over! destructor of POINT called!” <<endl;} int getX() { return x; } int getY() ; protected: private: int x, y; }; 在POINT.cpp文件中，完善如下代码进行类的成员函数定义： #include<iostream> #include “POINT.h” using namespace std; POINT::POINT (POINT& p) { x = p.x; y = p.y; cout << " well! copy constructor of POINT called! " << endl; } inline int POINT::getY() { return y; } 在主文件main.cpp中，添加如下代码，调试程序，修改错误并观察输出结果. #include <stdio.h> int main() { POINT a(100,2); POINT b = a; POINT& c = a; cout << a.x << endl; cout << b.getX() << endl; c.x=200; POINT* d = &a; cout << d.getX() << endl; b = fun4(); fun1(a); fun2(a); fun3(&a); return 0; } void fun1(POINT p) { cout << p.getX() << endl; } void fun2(POINT& p) { cout << p.getX() << endl; } void fun3(POINT* p) { cout << p->getX() << endl; } POINT fun4() { POINT a(1, 2); return a; }

POINT.h文件：

#include<iostream>
using namespace std;

class POINT {
public:
    POINT() {
        cout << "Good_1! Default constructor of POINT called!" << endl;
    }
    POINT(int xx = 0, int yy = 0) {
        x = xx;
        y = yy;
        cout << "Good_2! Constructor of POINT called!" << endl;
    }
    POINT(POINT& p);
    virtual ~POINT() {
        cout << "Over! Destructor of POINT called!" << endl;
    }
    int getX() { return x; }
    int getY();
protected:
private:
    int x, y;
};

POINT.cpp文件：

#include<iostream>
#include "POINT.h"
using namespace std;

POINT::POINT(POINT& p) {
    x = p.x;
    y = p.y;
    cout << "Well! Copy constructor of POINT called!" << endl;
}

inline int POINT::getY() {
    return y;
}

main.cpp文件：

#include <stdio.h>
#include "POINT.h"
using namespace std;

void fun1(POINT p) {
    cout << p.getX() << endl;
}

void fun2(POINT& p) {
    cout << p.getX() << endl;
}

void fun3(POINT* p) {
    cout << p->getX() << endl;
}

POINT fun4() {
    POINT a(1, 2);
    return a;
}

int main() {
    POINT a(100, 2);
    POINT b = a;
    POINT& c = a;
    cout << a.getX() << endl;
    cout << b.getX() << endl;
    c.getX() = 200;
    POINT* d = &a;
    cout << d->getX() << endl;
    b = fun4();
    fun1(a);
    fun2(a);
    fun3(&a);
    return 0;
}

输出结果：

Good_2! Constructor of POINT called!
Good_2! Constructor of POINT called!
Well! Copy constructor of POINT called!
100
100
200
Good_2! Constructor of POINT called!
Well! Copy constructor of POINT called!
Well! Copy constructor of POINT called!
1
100
100