PTA 7-23 复数四则运算（JAVA）

import java.util.Scanner;
public class Main {
    
    
    public static void main(String[] args) {
    
    
        Scanner scan = new Scanner(System.in);
        double a,b,c,d,e,f;
        a=scan.nextDouble();
        b=scan.nextDouble();
        c=scan.nextDouble();
        d=scan.nextDouble();
        System.out.printf("(%.1f%c%.1fi) + (%.1f%c%.1fi) = ",a,b<0?'-':'+',Math.abs(b),c,d<0?'-':'+',Math.abs(d));
        e=a+c;
        f=b+d;
        solve(e,f);
        System.out.printf("(%.1f%c%.1fi) - (%.1f%c%.1fi) = ",a,b<0?'-':'+',Math.abs(b),c,d<0?'-':'+',Math.abs(d));
        e=a-c;
        f=b-d;
        solve(e,f);
        System.out.printf("(%.1f%c%.1fi) * (%.1f%c%.1fi) = ",a,b<0?'-':'+',Math.abs(b),c,d<0?'-':'+',Math.abs(d));
        e=a*c-b*d;
        f=a*d+b*c;
        solve(e,f);
        System.out.printf("(%.1f%c%.1fi) / (%.1f%c%.1fi) = ",a,b<0?'-':'+',Math.abs(b),c,d<0?'-':'+',Math.abs(d));
        e=(a*c+b*d)/(c*c+d*d);
        f=(b*c-a*d)/(c*c+d*d);
        solve(e,f);
}
    static int judge(double x)
    {
    
    
        return Math.abs(x)<0.05?0:1;
    }

   static void solve(double e,double f)
    {
    
    
        if(judge(e)==0&&judge(f)==0){
    
    
            System.out.printf("0.0\n");
        }
        else if(judge(e)==0){
    
    
            System.out.printf("%.1fi\n",f);
        }
        else if(judge(f)==0){
    
    
            System.out.printf("%.1f\n",e);
        }
        else{
    
    
            System.out.printf("%.1f%c%.1fi\n",e,f<0?'-':'+',Math.abs(f));
        }
    }
}