c# 字串常用函數練習

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

namespace CSharp
{
    public class TestString
    {
        public TestString()
        {
            string[] sA = new string[5] { "H", "e", "l", "l", "o" };
            Console.WriteLine(String.Concat(sA));
            Console.WriteLine(String.Join("-",sA));

            string s = String.Join("", sA);
            Console.WriteLine(s);

            char[] c = s.ToCharArray();

            string sl = s.ToLower();
            string su = s.ToUpper();

            Console.WriteLine(sl + "--" + su);
            string s2 = s.PadLeft(10, '_');
            Console.WriteLine(s2);

            string s3 = s.PadRight(10, '_');
            Console.WriteLine(s3);

            string s4 = String.Join("-", sA);
            string[] s5 = s4.Split(new char[]{'-'});
            foreach (string s6 in s5)
            {
                Console.WriteLine(s6);
            }

            string s7 = s2.Trim();
            Console.WriteLine(s7);
            string s8 = s2.Trim(new char[] { '_' });
            Console.WriteLine(s8);

            //TrimEnd,TrimStart 同理.

            if (s2.StartsWith("H"))
            {
                Console.WriteLine("S2 was start with 'H'");
            }
            else
            {
                Console.WriteLine("S2 wasn't start with 'H'");
            }

            if (s2.EndsWith("o"))
            {
                Console.WriteLine("S2 was end with 'o'");
            }
            else
            {
                Console.WriteLine("S2 wasn't end with 'o'");
            }
            
            Console.WriteLine(s2.Substring(5,s2.Length-5));
            Console.WriteLine(s2.Remove(0, 5));

            Console.WriteLine(s2.Replace("l","i"));

            if (String.IsNullOrEmpty(s2))
            {
                Console.WriteLine("S2 Is NullOrEmpty");
            }
            else
            {
                Console.WriteLine("S2 Isn't NullOrEmpty");
            }

        }
    }
}