定义复数类Plurality Java 题目书求解答

定义复数类Plurality,该类具有加、减运算以及以返回复数格式（重写Object类中toString()）的功能，同时构造方法、实现加减运算的方法要体现方法的重载。最后编写测试类TestPlurality去验证创建复数类的功能。

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import java.util.Scanner;
/*
* 实现两个复数的加减运算
* */
public class PluralityDemo {
    // main方法
    public static void main(String[] a) {
        Scanner in=new Scanner(System.in);
        Plurality b = new Plurality(in.nextInt(), in.nextInt());
        Plurality c = new Plurality(in.nextInt(), in.nextInt());
        //输出复数的值
        System.out.println(b);
        System.out.println(c);
        //输出计算结果值
        System.out.println(b.add(c));
        System.out.println(b.minus(c));
    }
}
// Plurality类
class Plurality {
    private double m;// 实部
    private double n;// 虚部
    public Plurality(double m, double n) {
        this.m = m;
        this.n = n;
    }
    // add
    public Plurality add(Plurality c) {
        return new Plurality(m + c.m, n + c.n);
    }
    // minus
    public Plurality minus(Plurality c) {
        return new Plurality(m - c.m, n - c.n);
    }
    @Override
    public String toString() {
        String rtr_str = "";
        if (n > 0) {
            rtr_str =m + "+" + n + "i";
        }
        if (n == 0) {
            rtr_str =m+"";
        }
        if (n < 0) {
            rtr_str =m +""+ n + "i";
        }
        return rtr_str;
    }
}