Indexof的实现

我就是我 2021-12-24 15:15 399阅读 0赞

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][] 代码

1     class  Program  
  2     \{  
  3          static   void  Main( string \[\] args)  
  4         \{  
  5              string  str1  =   "" ;  
  6              string  str2  =   " 中 " ;  
  7   
  8             Console.WriteLine(str1.IndexOf(str2));  
  9             Console.WriteLine(StringIndexOf(str1, str2));  
 10   
 11             Console.ReadKey();  
 12         \}  
 13   
 14          /\*\*/ ///   <summary>   
 15          ///  实现字符串的IndexOf 功能    
 16          ///   </summary>   
 17          ///   <param name="strMain"></param>   
 18          ///   <param name="strExtre"></param>   
 19          ///   <returns></returns>   
 20          static   int  StringIndexOf( string  strMain,  string  strExtre)  
 21         \{  
 22              if  (strMain  ==   null   ||  strExtre  ==   null )  
 23                  throw   new  Exception( " String cannot be null. " );  
 24              if  (strExtre.Length  ==   0 )  return   0 ;  
 25              if  (strExtre.Length  >  strMain.Length)  return   \- 1 ;  
 26   
 27              // 返回值   
 28              int  index  =   \- 1 ;  
 29              // 获取附加字符串首字符    
 30              char  c  =  strExtre\[ 0 \];  
 31              // 在主字符串中搜索首字符   
 32              for  ( int  i  =   0 ; i  <  strMain.Length; i \++ )  
 33             \{  
 34                  // 不匹配的话继续搜索   
 35                  if  ( false   ==  strMain\[i\].Equals(c))  continue ;  
 36   
 37                  int  Length  =   1 ;  
 38                  // 从次首字符开始比较   
 39                  for  ( int  j  =   1 ; j  <  strExtre.Length; j \++ )  
 40                 \{  
 41                      if  ((i  \+  j)  >=  strMain.Length)  break ;  
 42                      if  ( false   ==  strMain\[i  \+  j\].Equals(strExtre\[j\]))  break ;  
 43                     Length \++ ;  
 44                 \}  
 45                  // 条件匹配即退出   
 46                  if  (Length  ==  strExtre.Length)  
 47                 \{  
 48                     index  =  i;  
 49                      break ;  
 50                 \}  
 51             \}  
 52   
 53              return  index;  
 54         \}  
 55     \}

转载于:https://www.cnblogs.com/hubcarl/archive/2010/03/07/1680187.html

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