Class PointXY

The class PointXY will be used below in questions in this exam.

class PointXY {

public:

PointXY() { x = 0; y = 0; }

void set(double a, double b) { x = a; y = b; }

double getx() const { return x; }

double gety() const { return y; }

private:

double x, y;

};

This question uses the class PointXY.

Declare a class Polygon as follows.

The data in class Polygon is an integer num and a pointer PointXY *pxy, both private.

class Polygon {

public: Polygon(int n); // write code

// copy constructor // write code

// assignment operator // write code

// destructor // write code

(return type) get_point(int n) const; // write code

void set_point(const PointXY &p, int n); // write code

int get_num() const { return num; } // nothing to do, code is given to you

private:

int num;

PointXY *pxy;

};

Write a non-default constructor with an input int n.

1. If n > 0, set num=n and dynamically allocate pxy to an array of length num.

2. Else if n ? 0, set num = 0 and pxy = NULL.

Write a copy constructor, assignment operator and destructor to perform appropriate copies and management of dynamic memory.

Write a method get point(int n).

1. Return the address of pxy[n] if the value of n is valid.

2. Else return NULL.

3. The method is const.

4. Write the function value to have the correct type.

Write a method set point(const PointXY &p, int n).

1. Set pxy[n] = p if the value of n is valid.

2. Else do nothing.