求大神解决问题！！复数类，其他都正常，一旦输入2+i 和 3-5i 结果就成了 2 ...

package com.ShiYan;

import java.io.*;

public class ShiYan03_01 {

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        Complex c, c1, c2;
        c = new Complex(0, 0);

        double Real[], Imginary[];
        Real = new double[2];
        Imginary = new double[2];
        String str;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        for (int i = 0; i < 2; i++) {
            System.out.println("请分别输入第" + (i + 1) + "个数的实部和虚部：");
            str = br.readLine();
            Real[i] = Double.parseDouble(str);
            str = br.readLine();
            Imginary[i] = Double.parseDouble(str);
        }
        c1 = new Complex(Real[0], Imginary[0]);
        c2 = new Complex(Real[1], Imginary[1]);
        int select;
        System.out.println("请选择想要进行的运算序号： 0.加     1.减     2.乘     3。除");
        System.out.println("请输入想要进行的运算（请输入相应运算序号）：");
        str = br.readLine();
        select = Integer.parseInt(str);
        if (select == 0)
            c = c.Add(c1, c2);
        else if (select == 1)
            c = c.Minus(c1, c2);
        else if (select == 2)
            c = c.Multiply(c1, c2);
        else if (select == 3)
            c = c.Divide(c1, c2);
        if (c.getImginaryPart() > 0)
            System.out.println(c.getRealPart() + "+" + c.getImginaryPart()
                    + "i");
        else
            System.out.println(c.getRealPart() + c.getImginaryPart() + "i");
    }

}

class Complex { // 构造复数类
    private double RealPart, ImginaryPart;

    public Complex(double r, double i) {// 构造函数
        RealPart = r;
        ImginaryPart = i;
    }

    public Complex() {// 无参构造函数
        RealPart = 0;
        ImginaryPart = 0;
    }

    public double getRealPart() {
        return RealPart;
    }

    public double getImginaryPart() {
        return ImginaryPart;
    }

    public Complex Add(Complex c1, Complex c2) {
        Complex sum = new Complex();
        sum.RealPart = c1.RealPart + c2.RealPart;
        sum.ImginaryPart = c1.ImginaryPart + c2.ImginaryPart;
        return sum;
    }

    public Complex Minus(Complex c1, Complex c2) {
        Complex minus = new Complex();
        minus.RealPart = c1.RealPart - c2.RealPart;
        minus.ImginaryPart = c1.ImginaryPart - c2.ImginaryPart;
        return minus;
    }

    public Complex Multiply(Complex c1, Complex c2) {
        Complex multiply = new Complex();
        multiply.RealPart = c1.RealPart * c2.RealPart - c1.ImginaryPart
                * c2.ImginaryPart;
        multiply.ImginaryPart = c1.ImginaryPart * c2.RealPart + c1.RealPart
                * c2.ImginaryPart;
        return multiply;
    }

    public Complex Divide(Complex c1, Complex c2) {
        Complex divide = new Complex();
        divide.RealPart = (c1.RealPart * c2.RealPart + c1.ImginaryPart
                * c2.ImginaryPart)
                / (c2.RealPart * c2.RealPart + c2.ImginaryPart
                        * c2.ImginaryPart);
        divide.ImginaryPart = (c1.ImginaryPart * c2.RealPart - c1.RealPart
                * c2.ImginaryPart)
                / (c2.RealPart * c2.RealPart + c2.ImginaryPart
                        * c2.ImginaryPart);
        return divide;
    }

}