Question

用java 编写一程序，求解一元二次方程：aX2+bX+c=0。参数a、b及c从命令行做参数输入 java

若以下回答无法解决问题，邀请你更新回答

Answer 1

以下程序在jdk5.0测试通过
import java.util.Scanner;

public class Test {

//一元二次方程式解法
private static X fx (int a,int b,int c) throws Exception{
X x = new X();
double m = b*b - 4*a*c;
if(m>=0){
x.x1=(-1*b+Math.sqrt(m))/(2*a);
x.x2=(-1*b-Math.sqrt(m))/(2*a);
return x;
}
else throw new Exception("无解");

}

public static void main(String[] args) {

try{
//输入参数a,b,c
Scanner cin=new Scanner(System.in);
System.out.print("a=");
int a = cin.nextInt();
System.out.print("b=");
int b = cin.nextInt();
System.out.print("c=");
int c = cin.nextInt();

//计算
X x=fx(a,b,c);

//显示
System.out.println("\n1x1="+x.x1+"\nx2="+x.x2);

}catch(Exception e){
System.out.println(e.getMessage());
}
}

}

//一元二次方程解集包装类
class X{
double x1;
double x2;
}

Answer 2

只能得到近似解