public class ComplexNumber {
    private double re;
    private double im;
    public static ComplexNumber add(ComplexNumber x, ComplexNumber y) {
        return  d(y);
    }
    
    public static ComplexNumber multiply(ComplexNumber x, ComplexNumber y) {
        return  ltiply(y);
    }
  
    public static ComplexNumber multiply(ComplexNumber x, double y) {
        return multiply(x, new ComplexNumber(y,0));
    }
    
    public ComplexNumber(double re, double im) {
          = re;
          = im;
    }
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb。
  append(""+re);
        if(im > 0) sb。append("+" + im + "i");
        else if(im < 0) sb。append("" + im + "i");
        return  String();
    }
    public double getAbs() { 
        return Math。
  sqrt(re*re+im*im); 
    }
    
    public double getAngle() { 
        return  an2(im,re); 
    }
    public double getRealPart() { 
        return re; 
    }
    
    public double getImaginaryPart() { 
        return im; 
    }
    
    public ComplexNumber add(ComplexNumber x) { 
        return new ComplexNumber(re+ , im+ ); 
    }
    
    public ComplexNumber multiply(ComplexNumber x) { 
        double nre = re*  - im* ;
        double nim = im*  + re* ;
        return new ComplexNumber(nre,nim);
    }
}。