import java.util.Scanner;

//ax^2+bx+c=0 求根

public class TestTwo {

public static void main(String[] args) {

double a,b,c;

Scanner sc=new Scanner(System.in);

System.out.println("輸入a,b,c三個數：");

System.out.print("輸入數a：");

a=sc.nextDouble();

System.out.print("輸入數b：");

b=sc.nextDouble();

System.out.print("輸入數c：");

c=sc.nextDouble();

qiuRoot(a, b, c);

}

static void qiuRoot(double a,double b,double c) {

double x1=0,x2=0;

double realpart=0, imagepart=0;

double disc=0;

//if(a!=0)

//float f1=3.0f; //3.00000000003214343214

//float f2=3.0f;//3.0000000000006453646543

if(Math.abs(a)<1e-6) { //說明a=0

System.out.println("這不是一個一元二次方程");

System.exit(0);

}else {

System.out.println("一元二次方程");

disc=b*b-4*a*c;

}

if(Math.abs(disc)<1e-6) {

System.out.println("有兩個相等的根："+(-b/(2*a)));

}else if (Math.abs(disc)>=1e-6) {

x1=(-b+Math.sqrt(disc))/(2*a);

x2=(-b-Math.sqrt(disc))/(2*a);

System.out.println("有兩個不相等的根："+"x1="+x1+" x2="+x2);

}else {