Java复数的加乘除运算

//主要是对零的处理，有什么不对的地方欢迎批评指正，一起进步
class complex{
    double a,b;
     public String toString() {
        return("实部："+a+"虚部:"+b);
    }
    void add(complex x,complex y) {
        double m,n;
        m = x.a+y.a;
        n = x.b+y.b;
        print(m,n);
    }
   void mult(complex x,complex y) {
        double m,n;
        n = x.b*y.a+x.a*y.b;
        m =x.a*y.a-x.b*y.b;
        print(m,n);
    }
   void dep(complex x,complex y) {
        double n = (x.a*y.a-x.b*y.b)/(y.a*y.a+y.b*y.b);
        double m = (x.b*y.a+x.a*y.b)/(y.a*y.a+y.b*y.b);
        if(y.a==0&&y.b==0)
            System.out.println("除法无意义\n");
        else
        {
            print(m,n);
        }
    }
    void print(double m,double n) {
        if(m!=0)
        {
            if(n>0) {
                System.out.println(m+"+");
                System.out.println(n+"i");
            }
            else if(n<0) {
                System.out.print(m);
                System.out.println(n+"i");
            }
            else
                System.out.println(m);
        }
        else {
            if(n!=0) {
                System.out.println(n+"i");
            }
            else
                System.out.println(m);
        }
    }
}
public class Javacomplex {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         complex n1,n2,n;
         n1 = new complex();
         n2 = new complex();
         n = new complex();
         n1.a = 1;n1.b=2;
         n2.a = -1;n2.b = 1;
         System.out.println(n1.toString());
         System.out.println(n2.toString());
         n.add(n1, n2);
         n.mult(n1, n2);
         n.dep(n1, n2);

    }

}