class Program
{
static void Main(string[] args)
{
Console.WriteLine("----------------------------test Append");
StringBuilder sb = new StringBuilder("Hello",100);
sb.Append(" World !");
Console.WriteLine(sb);
Console.WriteLine("----------------------------test Insert");
sb = new StringBuilder("Hello");
sb.Insert(2,"sss");
Console.WriteLine(sb);      //结果为:Hesssllo

Console.WriteLine("----------------------------test Remove");
sb = new StringBuilder("Hello");
sb.Remove(2,3);
Console.WriteLine(sb);      //结果为:He

Console.WriteLine("----------------------------test Replace");
sb = new StringBuilder("Hello");
sb.Replace("l", "M");
Console.WriteLine(sb);      //结果为:HeMMo
        }
}