题解 | #计算一元二次方程#

public class Main{
    public static void main(String [] args){
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
            Double a=sc.nextDouble();
             Double b=sc.nextDouble();
             Double c=sc.nextDouble();
            if(a==0){
                System.out.println("Not quadratic equation");
            }else{
                double x=Math.pow(b,2)-4*a*c;
                double x1=0.0;
                double x2=0.0;
                if(x==0){
                    x1=x2=(-b)/(2*a);
                    System.out.printf("x1=x2=%.2f\n",x1);
                }else if(x>0){
                    x1=(((-b)+Math.sqrt(x))/(2*a));
                    x2=(((-b)-Math.sqrt(x))/(2*a));
                    if(x1>x2){
                        double tmp=0.0;
                        tmp=x1;
                        x1=x2;
                        x2=tmp;
                        System.out.printf("x1=%.2f;x2=%.2f\n",x1,x2);
                    }else{
                         System.out.printf("x1=%.2f;x2=%.2f\n",x1,x2);
                    }
                }else if(x<0){
                    double real=(-b)/(2*a);
                    if(b==0.00){
                        real=0.00;
}
                    double imag=Math.sqrt(-x)/(2*a);
                   System.out.printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n",real,imag,real,imag);
                }
            }
        }
    }
}