java - 在java中显示复数

Question

我今天的目标是能够对复数 (a+bi) 进行加减乘除，并以某种方式显示该数据。当我尝试创建一种除复数的方法时，我知道困难会出现。如果我的数学正确或 ((29-11i)/74)，它应该显示大约 0.39189-.1486i。我得到的输出是:-0.041666666666666664+0.4583333333333333i，这是不正确的。

你能帮我找出 ComplexDiv 方法中的错误吗？

代码如下:

public String ComplexDiv(ComplexNumbers other) {

        String r = Double.toString(((real*other.real)-(complex*other.complex))
                / ((other.real * other.real)-(other.complex * other.complex)));

        String c = Double.toString((-(real*other.complex)+(other.real*complex)) 
                / ((other.real * other.real)-(other.complex * other.complex)));

        return r + "+" + c + "i";
    }

这是调用该方法的测试类:

public class ComplexTest {
    public static void main(String[] args) {
        ComplexNumbers c1 = new ComplexNumbers();
        ComplexNumbers c2 = new ComplexNumbers();

        c1.real = 3;
        c1.complex = 2;
        c2.real = 5;
        c2.complex = 7;

        System.out.println(c1.ComplexAdd(c2));
        System.out.println(c1.ComplexSub(c2));
        System.out.println(c1.ComplexMult(c2));
        System.out.println(c1.ComplexDiv(c2));
        System.out.println(c1.findConjugate());
    }
}

奖励问题:知道如何用分数形式而不是小数形式表示我的答案吗？

这里是整个 ComplexNumbers 类，只是为了让您大致了解我的方法:

package exerciseslearningjava;

public class ComplexNumbers {

    public double real;
    public double complex;
    public double realConvert;
    public double compConvert;


    public String ComplexAdd(ComplexNumbers other) {

        String r = Double.toString(real + other.real);
        String c = Double.toString(complex + other.complex);

        return r + "+" + c + "i";
    }
    public String ComplexSub(ComplexNumbers other) {

        String r = Double.toString(real - other.real);
        String c = Double.toString(complex - other.complex);

        return r + c + "i";
    }
    public String ComplexMult(ComplexNumbers other) {

        String r = Double.toString((real * other.real) - (complex*other.complex));
        String c = Double.toString((real * other.complex)+(complex*other.real));

        return r + "+" + c + "i";

    }
    public String ComplexDiv(ComplexNumbers other) {

        String r = Double.toString(((real*other.real)-(complex*other.complex))
                / ((other.real * other.real)-(other.complex * other.complex)));

        String c = Double.toString((-(real*other.complex)+(other.real*complex)) 
                / ((other.real * other.real)-(other.complex * other.complex)));

        return r + "+" + c + "i";
    }
    public String findConjugate() {
        String r = Double.toString(real);
        String c = Double.toString(complex);

        return r + "-" + c + "i";
    }
}

Answer 1

你的分母:

((other.real * other.real) - (other.complex * other.complex))

不应该是:

((other.real * other.real) + (other.complex * other.complex))

由于您是通过将复数乘以其共轭得到的:

(a + bi) * (a - bi) = (a * a) - (b * b * i * i)

但是因为 i * i 是 -1，这变成了:

(a + bi) * (a - bi) = (a * a) + (b * b)

另外，顺便说一句，当我看到字符串被用来表示数值时，我的后脑勺都会有不好的感觉。为什么要使用字符串？为什么不是 float 或 BigDecimal？