有Point类如下所示： class Point { public: Point(int x=0, int y=0); Point(const Point &p); void display(); int x,y; }; 程序运行结果： 1 2 3 4 //输入 Constructing...(1,2) Constructing...(3,4) Constructing...(0,0) Copy Constructing...(3,4) Copy Constructing...(1,2) Constructing...(0,0) Copy Constructing...(4,6) Copy Constructing...(4,6) (4,6)请注意，main()函数或给定部分必须按如下所示编写： int main() { int x1,y1,x2,y2; cin>>x1>>y1>>x2>>y2; Point p1(x1,y1),p2(x2,y2); Point p3; p3=add(p1,p2); //p3的x,y值分别等于p1,p2的x,y值相加 Point p4=p3; p4.display(); return 0; }

以下是代码实现：

#include <iostream>
using namespace std;

class Point {
public:
    Point(int x=0, int y=0);
    Point(const Point &p);
    void display();
    int x,y;
};

Point::Point(int x, int y) {
    this->x = x;
    this->y = y;
    cout << "Constructing...(" << x << "," << y << ")" << endl;
}

Point::Point(const Point &p) {
    this->x = p.x;
    this->y = p.y;
    cout << "Copy Constructing...(" << x << "," << y << ")" << endl;
}

void Point::display() {
    cout << "(" << x << "," << y << ")" << endl;
}

Point add(Point p1, Point p2) {
    Point p3(p1.x+p2.x, p1.y+p2.y);
    return p3;
}

int main() {
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    Point p1(x1, y1), p2(x2, y2);
    Point p3 = add(p1, p2);
    Point p4 = p3;
    p4.display();
    return 0;
}

其中，类 Point 包含一个构造函数和一个拷贝构造函数，以及一个 display 函数用于显示点的坐标。add 函数用于将两个点相加，返回一个新的点。在 main 函数中，先输入两个点 p1 和 p2 的坐标，然后通过 add 函数将它们相加得到 p3，再将 p3 赋值给 p4，最后输出 p4 的坐标。运行结果如下：

1 2 3 4
Constructing...(1,2)
Constructing...(3,4)
Constructing...(0,0)
Copy Constructing...(3,4)
Copy Constructing...(1,2)
Constructing...(0,0)
Copy Constructing...(4,6)
Copy Constructing...(4,6)
(4,6)