1601: 蓝桥杯算法训练VIP-一元三次方程求解 程序能用不知道为什么报运行错误QAQ

解题思路:

注意事项:

参考代码:

import java.util.Scanner;

public class a9 {

/**

* @param args

*/

//a*x*x*x+b*x*x+c*x+d

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner scanner=new Scanner(System.in);

double a=scanner.nextInt();

double b=scanner.nextInt();

double c=scanner.nextInt();

double d=scanner.nextInt();

double arr[]=new double[3];

int count=0;

for (double i = -100; i <100; i++) {

if ((a*i*i*i+b*i*i+c*i+d)==0&&a!=0) {

arr[count++]=i;

}

}

//卡丹公式法验证

if ((arr[0]+arr[1]+arr[2])==-(b/a)||(1/arr[1]+1/arr[0]+1/arr[2])==-(c/d)||arr[0]*arr[1]*arr[2]==-(d/a))

//根与系数的关系判断

 {

for (int j = 0; j < 3; j++) {

System.out.print(String.format("%.2f", arr[j])+" ");

}

}

}

}