字符串转换成整形值

  1 enum STATUS{STRNULL=0, STREMPTY, STRINVALID, STROVERFLOW, STRVALID};
  2 enum SIGN{NEGATIVE=0, POSITIVE};
  3 enum STATUS status = STRVALID;
  4 enum SIGN sign = POSITIVE;
  5 int str2int(const char *str)
  6 {
  7     long long num = 0;
  8 
  9     if (str == NULL)
 10     {
 11         status = STRNULL;
 12 
 13         return 0; 
 14     }
 15     while (*str == ' ')
 16     {
 17         str++;
 18     }
 19 
 20     if (*str == '-' || *str == '+')
 21     {    
 22         if (*str == '-')
 23         {
 24             sign = NEGATIVE;
 25         }
 26         if ( *(str+1) == '