java声明复数的类complex，实现复数的加减乘除运算。

以下是JAVA声明复数的类Complex，实现复数的加减乘除运算：

public class Complex {
    private double real; // 实部
    private double imaginary; // 虚部

    // 构造函数
    public Complex(double real, double imaginary) {
        this.real = real;
        this.imaginary = imaginary;
    }

    // 获取实部
    public double getReal() {
        return real;
    }

    // 获取虚部
    public double getImaginary() {
        return imaginary;
    }

    // 复数加法
    public Complex add(Complex other) {
        double realPart = this.real + other.real;
        double imaginaryPart = this.imaginary + other.imaginary;
        return new Complex(realPart, imaginaryPart);
    }

    // 复数减法
    public Complex subtract(Complex other) {
        double realPart = this.real - other.real;
        double imaginaryPart = this.imaginary - other.imaginary;
        return new Complex(realPart, imaginaryPart);
    }

    // 复数乘法
    public Complex multiply(Complex other) {
        double realPart = this.real * other.real - this.imaginary * other.imaginary;
        double imaginaryPart = this.real * other.imaginary + this.imaginary * other.real;
        return new Complex(realPart, imaginaryPart);
    }

    // 复数除法
    public Complex divide(Complex other) {
        double denominator = other.real * other.real + other.imaginary * other.imaginary;
        double realPart = (this.real * other.real + this.imaginary * other.imaginary) / denominator;
        double imaginaryPart = (this.imaginary * other.real - this.real * other.imaginary) / denominator;
        return new Complex(realPart, imaginaryPart);
    }

    // 复数转字符串
    public String toString() {
        if (imaginary == 0) {
            return Double.toString(real);
        } else if (real == 0) {
            return Double.toString(imaginary) + "i";
        } else {
            return Double.toString(real) + (imaginary > 0 ? "+" : "-") + Double.toString(Math.abs(imaginary)) + "i";
        }
    }
}

使用方法如下：

Complex a = new Complex(1, 2);
Complex b = new Complex(3, 4);

Complex c = a.add(b);
System.out.println(a + " + " + b + " = " + c);

Complex d = a.subtract(b);
System.out.println(a + " - " + b + " = " + d);

Complex e = a.multiply(b);
System.out.println(a + " * " + b + " = " + e);

Complex f = a.divide(b);
System.out.println(a + " / " + b + " = " + f);

运行结果如下：

1.0+2.0i + 3.0+4.0i = 4.0+6.0i
1.0+2.0i - 3.0+4.0i = -2.0-2.0i
1.0+2.0i * 3.0+4.0i = -5.0+10.0i
1.0+2.0i / 3.0+4.0i = 0.44+0.08i