using System;

using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 {     class Program     {                 static void Main(string[] args)         {             //字符串处理             string s = "hello";             //1,得到字符串的长度             Console.WriteLine("字符串的长度"+s.Length);             //2,利用数组操作字符串 只能读不能写 字符串一旦声明 ，不能改变             Console.WriteLine("第一个字符" + s[0]);             //3,转换为字符             char[] arr = s.ToCharArray();             arr[0] = 'A';             //4，利用数组构造字符串             s = new string(arr);             Console.WriteLine(s);             //5,字符串转换成小写             String t = s.ToLower();             Console.WriteLine(t);             //6,转换成大写             t = s.ToUpper();             Console.WriteLine(t);             //7,去掉空白两边             Console.WriteLine(s.Trim());             //8,字符串的比较             Console.WriteLine("aello".Equals(s));             Console.WriteLine("aello".Equals(s, StringComparison.OrdinalIgnoreCase)); //忽略大小写的比较             Console.WriteLine("Aello" == s); //==区分大小写的比较             //9,分割字符串             s = "aaa,bbb,ccc,,   ddd|sdf|dddd|ddd";             string[] strArr = s.Split(',','|');             foreach (string temp in strArr)             {                 Console.WriteLine(temp);             }             //             也可以换成字符串的数组             strArr = s.Split(new char[]{','}, StringSplitOptions.RemoveEmptyEntries) ;//移除空的元素             foreach(string strtemp in strArr)             {                 Console.WriteLine(strtemp);             }             //10.字符串替换             s = "11111";             string temp2 = s.Replace("11", "22");             Console.WriteLine(temp2);             //11,字符串截取             s = "1234567890";             Console.WriteLine(s.Substring(2));  //从索引2号开始截取             Console.WriteLine(s.Substring(2,4));  //                           ，截取4个字符             //12,判断是否含有子川             Console.WriteLine(s.Contains("345"));             //13,判断字符串是否以什么开头             Console.WriteLine(s.StartsWith("123"));             //s.EndsWith();             Console.ReadKey();         }     } }