程序代码：

package examination;

public class ImaginaryNumber implements Comparable<ImaginaryNumber> 
{
    public ImaginaryNumber(int n, int i)
    {
        realnum = n;
        imanum = i;
    }

    public ImaginaryNumber(int n)
    {
        realnum = n;
        imanum = 0;
    }

    public String toString()
    {
        String s = realnum + "+" + imanum + "i";
        return s;
    }

    public boolean equals(ImaginaryNumber i)
    {
        if (this.realnum == i.realnum)
        {
            if (this.imanum == i.imanum)
                return true;
        }
        return false;
    }

    public int hashCode()
    {
        int h = 31;
        h = 31 * h + realnum;
        h = 31 * h + imanum;
        return h;
    }

    private int realnum;
    private int imanum;

    @Override
    public int compareTo(Imanum other)
    {

        double r = Math.sqrt(Math.pow(this.realnum, 2)
                + Math.pow(this.imanum, 2));
        double o = Math.sqrt(Math.pow(other.realnum, 2)
                + Math.pow(other.imanum, 2));
        if (r > o)
            return 1;
        if (r < o)
            return -1;
        return 0;
    }
}

程序代码：

package examination;

public class ImaginaryNumber implements Comparable<ImaginaryNumber> 
{
    public ImaginaryNumber(double re, double im)//带参数构造函数
    {
        realpart = re;
        imaginarypart = im;
    }
    
    public double getRealpart()
    {
        return realpart;
    }
    
    public double getImaginarypart()
    {
        return imaginarypart;
    }

    public String toString()
    {
        String s =getRealpart() + "+" + getImaginarypart() + "i";
        return s;
    }

    public boolean equals(ImaginaryNumber other)
    {
        if (this.getRealpart() == other.getRealpart())
        {
            if (this.getImaginarypart() == other.getImaginarypart())
                return true;
        }
        return false;
    }

    public int hashCode()
    {
        return 3*new Double(getRealpart()).hashCode()+5*new Double(getImaginarypart()).hashCode();
    }

    private double realpart;
    private double imaginarypart;

    public int compareTo(ImaginaryNumber otherObject)
    {
        ImaginaryNumber other = (ImaginaryNumber) otherObject;        
        double r = Math.sqrt(Math.pow(this.getRealpart(), 2)
                + Math.pow(this.getImaginarypart(), 2));
        double s = Math.sqrt(Math.pow(other.getRealpart(), 2)
                + Math.pow(other.getImaginarypart(), 2));
        if (r > s)
            return 1;
        if (r < s)
            return -1;
        return 0;
     }
}