C# print diamond pattern

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

namespace 打印菱形图案
{
    class Program
    {
        static void Main(string[] args)
        {
            Print p = new Print();
            Console.WriteLine("请输入组成菱形字符（长度为1的字符）：");
            var str = Console.ReadLine();
            Console.WriteLine("请输入菱形上半身高度(为使不影响效果不要大于10)：");
            int cenNum = Int32.Parse(Console.ReadLine());
            p.show(str, cenNum);
            Console.ReadKey();
        }
    }

    class Print
    {
        public void show(string str, int cenNum)
        {
            //string str = "*";
            string strBei = str;
            string strk = " ";

            //int cenNum = 4;
            for (int j = 0; j < cenNum; j++)
            {
                strk += strk;
            }
            for (int i = 0; i < cenNum; i++)
            {
                Console.WriteLine(strk + str);
                strk = strk.Substring(0, strk.Length - 1);//去除最后一个空格
                str += strBei + strBei;
            }
            str = str.Substring(0, str.Length - 2);
            strk += " ";
            for (int k = 0; k < cenNum - 1; k++)
            {
                strk += " ";
                str = str.Substring(0, str.Length - 2);//去除最后两个星号
                Console.WriteLine(strk + str);

            }
        }
    }
}