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