complex

  编写一个复数类，可以进行复数加法和减法运算。编写一个包含main方法的类（应用程序）测试该复数类。要求该复数类至少包含一个无参的构造方法和一个带参的构造方法；数据成员包括复数的实部和虚部，为double类型；包括两个方法，分别实现复数的加法和减法运算。(Write a complex class, which can add and subtract complex numbers. Write a class (application) containing the main method to test the complex class. The complex class is required to include at least one parametric construction method and one parametric construction method; the data members include the real and imaginary parts of the complex, which are of double type; and two methods are included to realize the addition and subtraction operations of the complex respectively.)