編寫一個復數類，可以進行復數加法和減法運算。編寫一個包含main方法的類（應用程序）測試該復數類。要求該復數類至少包含一個無參的構造方法和一個帶參的構造方法；數據成員包括復數的實部和虛部，為double類型；包括兩個方法，分別實現復數的加法和減法運算。代碼import java.util.Scanner;public class ComplexNum { double RealNum; double ImagNum; public ComplexNum() { Scanner input=new Scanner(System.in); RealNum=input.nextDouble(); ImagNum=input.nextDouble(); //ComplexNum(RealNum,ImagNum); } public ComplexNum(double RealNum,double ImagNum) { this.RealNum=RealNum; this.ImagNum=ImagNum;? ? } public ComplexNum add(ComplexNum b) { double RealNum1=this.RealNum; ? ? double ImagNum1=this.ImagNum; ? ? double LastReal=RealNum+RealNum1; ? ? double LastImag=ImagNum+ImagNum1; ? ? ComplexNum result=new ComplexNum(LastReal,LastImag); ? ? return result; } public ComplexNum mul(ComplexNum b) { double RealNum1=this.RealNum; ? ? double ImagNum1=this.ImagNum; ? ? double LastReal=RealNum-RealNum1; ? ? double LastImag=ImagNum-ImagNum1; ? ? ComplexNum result=new ComplexNum(LastReal,LastImag); ? ? return result; } public void printf() { if(ImagNum>0) { System.out.println(ImagNum+"+"+"j"+RealNum); } else if(ImagNum<0) { System.out.println(ImagNum+"-"+"j"+RealNum); } else { System.out.println(RealNum); } } public static void main(String[] args) { System.out.println("請輸入第一個復數的實部和虛部"); ComplexNum a=new ComplexNum(); System.out.println("請輸入第二個復數的實部和虛部"); ComplexNum b=new ComplexNum();? ? ? ?? ComplexNum add=a.add(b); ComplexNum mul=a.mul(b); add.printf(); mul.printf(); }}