提示"not all code paths return"望高手看看!谢谢!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;namespace _21p
{
    class DistriCards
    {
        private string hongtao="\u0003";
        private string fangpian="\u0004";
        private string meihua="\u0005";
        private string heitao="\u0006";
        private int num;
        Random Number = new Random();
        public void DistriPics()
        {
            switch (DateTime.Now.Second%4)
            {
                case 1: Console.WriteLine(hongtao); break;
                case 2: Console.WriteLine(fangpian); break;
                case 3: Console.WriteLine(meihua); break;
                case 4: Console.WriteLine(heitao); break;
                //default: Console.WriteLine("Distribute Card Failed"); break;
            }
        }
        public int DistriNums()
        {
            switch (num=Number.Next(1,13))
            {
                case 1: Console.Write("A"); return 1; break;
                case 2: Console.Write("2"); return 2; break;
                case 3: Console.Write("3"); return 3; break;
                case 4: Console.Write("4"); return 4; break;
                case 5: Console.Write("5"); return 5; break;
                case 6: Console.Write("6"); return 6; break;
                case 7: Console.Write("7"); return 7; break;
                case 8: Console.Write("8"); return 8; break;
                case 9: Console.Write("9"); return 9; break;
                case 10: Console.Write("10"); return 10; break;
                case 11: Console.Write("J"); return 1; break;
                case 12: Console.Write("Q");return 1 ; break;
                case 13: Console.Write("K"); return 1; break;
            }
        }
    }
}