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

namespace ConsoleOverLoads
{
    class Program
    {
          static int sum(int x, int y)		// 傳回兩數相加
          {
                return (x + y);
          }
          static int sum(int x, int y, int z) 	// 傳回三數相加
          {
                return (x + y + z);
          }
          static string sum(string x, string y)  // 傳回兩個字串合併結果
          {
                return (x + y);
          }
          // 傳回三個字串合併結果
          static string sum(string x, string y, string z)
          {
                return (x + y + z);
          }

        static void Main(string[] args)
        {
               Console.WriteLine("1. sum(10,20)={0}", sum(10, 20));
               Console.WriteLine("2. sum(10,20,30)={0}", sum(10, 20, 30));

               Console.WriteLine("3. sum(\"Good\", \"Day!\")={0}", sum("Good ", "Day!"));

               string str1, str2, str3;
               str1 = "Have a "; str2 = "Good "; str3 = "Day!";              
               Console.WriteLine("4. sum(\"{0}\",\"{1}\",\"{2}\") = {3}", str1, str2, str3, sum(str1, str2, str3));

               Console.Read();
        }
    }
}