1、　　矩形

编写C++程序完成以下功能：

（1）　　定义一个Point类，其属性包括点的坐标，提供计算两点之间距离的方法；

（2）　　定义一个矩形类，其属性包括左上角和右下角两个点，提供计算面积的方法；

（3）　　创建一个矩形对象，提示用户输入矩形左上角和右下角的坐标；

（4）　　观察矩形对象以及Point类成员的构造函数与析构函数的调用；

（5）　　计算其面积，并输出。

-1, rectangular write C++ program completed the following features: (1) the definition of a Point class, its properties include the point coordinates, distance calculation between two points　(2) to define a rectangle class, its properties, including the top left and right lower corner of the two points, the method of calculating the area　(3) create a rectangular object, the user is prompted to enter the rectangular coordinates of the upper left and lower right corners of the　(4) observed a rectangular object as well as a member of the Point class constructor and destructor call　 (5) to calculate the area, and outputs.