package hwoneweek;
//求方程aX^2+bX+c=0的实数解。要求：a、b、c的值从键盘输入

import java.util.Scanner;
public class xcheng{
	public static void main(String[] args){
		double x = 0;
		double i ,i1 = 0;
		System.out.println("求方程aX^2+bX+c=0的实数解,请按提示输入！");	
		Scanner input = new Scanner(System.in);
		System.out.println("请输入a:");	
		double a = input.nextDouble();
		System.out.println("请输入b（注意a和b不能同时为0）:");
		double b = input.nextDouble();
		System.out.println("请输入c:");		
		double c = input.nextDouble();
		i = b*b-4*a*c;	
		if(a == 0){
			if(b == 0)
				System.out.println("a和b同时为0，输入错误!!!");
			else{
				x = c/b;
				System.out.println("x="+x);
			}
		}			
		else{
			if(i<0)
				System.out.println("方程无实数解！");
			else{
				i1 = Math.sqrt(i);
				System.out.println("方程的实数解为：");
				x = (-b+i1)/(2*a);
				System.out.println("x1="+x);
				x = (-b-i1)/(2*a);
				System.out.println("x2="+x);
			}			
		}						
	}					
}