第一次只出现一次的字符

 1 #include <string>
 2 #include "stdafx.h"
 3 
 4 char FirstNotRepeatingChar(char* pString)
 5 {
 6      if(pString == NULL)
 7          return ‘\0‘;
 8 
 9      const int tableSize = 256;
10      unsigned int hashTable[tableSize];
11      for(unsigned int i = 0;i < tableSize ; ++i)
12          hashTable[i] = 0;
13 
14      char* pHashKey = pString;
15      while(*pHashKey != ‘\0‘)
16          hashTable[*(pHashKey++)] ++;
17 
18      pHashKey = pString;
19      while(*pHashKey != ‘\0‘)
20      {
21          if(hashTable[*pHashKey] == 1)
22              return *pHashKey;
23 
24          pHashKey ++ ;
25      }
26 
27      return ‘\0‘;
28  }
29 
30 
31 int main()
32 {
33     
34     char* pString = "google";
35     printf("%c\n", FirstNotRepeatingChar(pString));
36     
37     pString = "abcdefg";
38     printf("%c\n", FirstNotRepeatingChar(pString));
39     
40     return 0;
41 }