09.24.函数多个返回值

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {

        //out 变成输出参数，通过out
        public double jieguo(double a, double b, double c, out double x1, out double x2)
        {


            double de = Math.Sqrt(b * b - 4 * a * c);
            x1 = 0;
            x2 = 0;
            if (a == 0)
            { return 3; }

            else
            {
            if (de > 0)
            {
                x1 = (-b + de) / 2 * a;
                x2 = (-b - de) / 2 * a;
                return 2;

            }

            else if (de == 0)
            {
                x1 = (-b + de) / 2 * a;
                x2 = x1;
                return 1;

            }
            else
            {
                return 0;


            }
        }}

        static void Main(string[] args)
        {

            Console.Write("请输入a=");
            double a = double.Parse(Console.ReadLine());
            Console.Write("请输入b=");
            double b = double.Parse(Console.ReadLine());
            Console.Write("请输入c=");
            double c = double.Parse(Console.ReadLine());
            double x1;
            double x2;
            double  f = new Program().jieguo(a, b, c, out x1, out x2);
            Console.ReadLine();
            if (f == 2)
            { Console.WriteLine("此方程有两个不相等实根"+x1 +"  "+x2 ); }

            if (f == 1)
            { Console.WriteLine("此方程有两个相等实根"+x1 +"  "+x2); }
            if (f == 0)
            { Console.WriteLine("此方程没有 实根"); }
            if (f == 3)
            { Console.WriteLine("此方程不是一元二次方程"); }


            Console.ReadLine();


        }

       
    }
}