：构建一个圆类Circle，其成员为圆心的坐标(x,y)和圆半径r，并设计构造函数（可以赋初值也可以不赋初值），析构函数（可以什么都不做，只打印信息，表示其被调用），设置新值成员函数Set(), 取圆心坐标成员函数GetX()、GetY()，取圆半径成员函数GetR()，打印成员值成员函数Print()，计算圆面积成员函数Area()。并用此类定义长度为10的对象数组，每个对象的圆心的坐标(x,y)和圆半径r由随机数rand()产生，打印每个对象的(x,y)、r和面积；然后将对象数组按照其r值从小到大排序，并打印排序后每个对象的(x,y)、r和面积；并计算打印出所有对象的平均(x,y)、平均r和平均面积。

#include <stdlib.h>

void main()

{ int i

　　srand(0) // srand为随机数序列赋初值，可以随意给

　　for (i=0 i<10 i++)

　　{　　x = rand() y = rand() r = rand() }

}

-: A round-class Circle, whose members are the center coordinates (x, y) and radius of the circle r, and design constructor (initial value may not be given the initial value), the destructor (you can do nothing, print information only, which means that it is called), set the new value of the member function set () member function to take center coordinates getX (), getY (), take a round the radius of members the function GETR () member function Print Print member values ​ ​ () calculate the area of ​ ​ a circle member function area (). And 10 for the array of objects with such a defined length, the center coordinates (x, y) of each object and the circle of radius r by a random number rand () to generate print (x, y), r and area of ​ ​ each object　then the array of objects in accordance with the r value from small to large order, and print sorting each object (x, y), r and area　print out and calculate the average of all the objects (x, y), the average r an