3.　　定义一个复数(z=x+iy)类Complex，包含：

两个属性：实部x和虚部y

默认构造函数 Complex()，设置x=0,y=0

构造函数：Complex(int i,int j)

显示复数的方法：showComp()将其显示为如： 5+8i或5-8i 的形式。

求两个复数的和的方法：（参数是两个复数类对象，返回值是复数类对象）public Complex addComp(Complex C1,Complex C2)

求两个复数的差的方法：（参数是两个复数类对象，返回值是复数类对象）public Complex subComp(Complex C1,Complex C2)

-. A class definition Point, represents a Point, public property have x and y, a method that Point coordinates show (), there are two arguments constructor respectively to x, y assignment, in the main method constructed of two objects, to create a method (getMiddle) to take two make the Point of the line of coordinate, parameters for 2 Point object, call this method after get a new Point, write Application, display the object coordinates.

1. Define a plural (z = x+ iy) kind of Complex, including:

Two attributes: real part x and imaginary part y

The default constructor Complex (), set x = 0, y = 0

The constructor: Complex (int I, int j)

Show the plural method: showComp () will be the display for such as: 5+ 8 I or 5-8 I form.

For two of the plural and methods: (parameters are two plural class object, the return value is a plural class object) public Complex addComp (Complex C1, Complex C2)

For two of the plural of poor methods: (parameters are two plural class object, the return v