使用JAVA编程实现复数类ComplexNumber

属性包括实数部分和虚数部分；方法有加法add和减法subtract；编写图形界面的程序验证以上的复数类，接收用户输入的复数的实部和虚部，计算复数与复数、复数与实数的加、减的操作。
评定标准：正确地使用重载概念定义复数类，正确地编写测试类验证复数类的加、减操作。

import java.applet.Applet;
import java.awt.Button;
import java.awt.Label;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class ComplexTest extends Applet implements ActionListener{

Label firstReal, firstImg;
TextField firstRealNum, firstImgNum;

Label secondReal, secondImg;
TextField secondRealNum, secondImgNum;

Button add = new Button("Add");
Button subtract = new Button("Subtract");

TextField addResult, subtractResult;

public void init(){

firstReal = new Label("First Complex Real Number: ");
firstRealNum = new TextField(7);
super.add(firstReal);
super.add(firstRealNum);

firstImg = new Label("First Complex Imaginary Number: ");
firstImgNum = new TextField(7);
super.add(firstImg);
super.add(firstImgNum);

secondReal = new Label("Second Complex Real Number: ");
secondRealNum = new TextField(7);
super.add(secondReal);
super.add(secondRealNum);

secondImg = new Label("Second Complex Imaginary Number: ");
secondImgNum = new TextField(7);
super.add(secondImg);
super.add(secondImgNum);

super.add(add);
addResult = new TextField(7);
super.add(addResult);

super.add(subtract);
subtractResult = new TextField(7);
super.add(subtractResult);

add.addActionListener(this);
subtract.addActionListener(this);
}

public void actionPerformed(ActionEvent e) {

double firstComplxReal = Double.parseDouble(firstRealNum.getText());
double firstComplxImg = Double.parseDouble(firstImgNum.getText());

double secondComplxReal = Double.parseDouble(secondRealNum.getText());
double secondComplxImg = Double.parseDouble(secondImgNum.getText());

ComplexNumber complxNum1 = new ComplexNumber(firstComplxReal, firstComplxImg);
ComplexNumber complxNum2 = new ComplexNumber(secondComplxReal, secondComplxImg);

addResult.setText(complxNum1.add(complxNum2).toString());
subtractResult.setText(complxNum1.subtract(complxNum2).toString());

}
}

class ComplexNumber{

private double real;
private double imaginary;

public ComplexNumber(double realNum, double imaginaryNum){
this.real = realNum;
this.imaginary = imaginaryNum;
}

// (a+bi) + (c+di) = (a+b) + (c+d)i
public ComplexNumber add(ComplexNumber complexNum2){

double newRealPart = this.real + complexNum2.getReal();
double newImgPart = this.imaginary + complexNum2.getImaginary();

return new ComplexNumber(newRealPart, newImgPart);
}

//(a+bi) - (c+di) = (a-b) - (c-d)i
public ComplexNumber subtract(ComplexNumber complexNum2){
double newRealPart = this.real - complexNum2.getReal();
double newImgPart = this.imaginary - complexNum2.getImaginary();

return new ComplexNumber(newRealPart, newImgPart);
}

public double getImaginary() {
return imaginary;
}

public void setImaginary(double imaginary) {
this.imaginary = imaginary;
}

public double getReal() {
return real;
}

public void setReal(double real) {
this.real = real;
}

public String toString(){
return real + "+" + imaginary + "i";
}

}