使用C语言提取子字符串及判断对称子字符串最大长度

#include <stdio.h>/*处理中文字符*//*遍历字符串，非ASCII字符读取2个字节，ASCII读取一个字节，获取字符串长度*/int StrLenU(const char* string){   int len = 0 ;   const char* p = string;   while(*p++ != '/0')   {     if(*p > 0x80 || *p < 0)     {      p++;     }     len++;   }   return len;}/*遍历字符串，非ASCII字符读取2个字节，ASCII读取一个字节，返回指定位置的字符串指针，默认从1开始*/char* StrSetPosU(const char* string,int pos){   char* result;   result = string;   while (result != NULL && *result != '/0' && pos > 1)   {     if(*result > 0x80 || *result < 0)     {       result++;     }     result++;     pos--;   }   if(pos!=0)     return result;   return '/0';}/*获取指定内存中的字符串个数，中文字符作为一个字符*/int StrLenMemU(const char* string,int size){     int len = 0 ;   const char* p = string;   while(*p++ != '/0' && size > 0)   {     if(*p > 0x80 || *p < 0)     {      p++;      size--;      }     size-- ;     len++;   }   return len;}/*可取中文字符串，当number为-1等负数时，取从start开始的剩余所有字符，默认从1开始*/char* StringSubU(const char* string,int start,int number){   int len = StrLenU(string) ;   if(start>len)   {     printf("Start %d is too big than string length %d!/n",start,len);     return NULL;   }   int bufsize = 0;   int num = number;   const char* p = string;   const char* start_char =string;   /*重置指针，获取指定开始位置*/   p = StrSetPosU(string,start);   start_char = p;   /*当取值为负值时，则取全部值*/   if(number < 0)   {     while(*p != '/0')     {      p++;      bufsize++;     }   }   else   {     while(1)     {      /*当指针移到末尾，而且还没有获取指定数的字符时，说明此时指定字符数过多，将会取剩下的所有值*/      if(*p == '/0' && num > 0)      {        printf("Number : %d is to big!/n",number);        break;      }      /*当num为0时，说明读取字符已经满足要求*/      else if(num ==0 )        break;      /*当字符为ASCII时，*/      if(*p > 0x80 || *p < 0)      {        bufsize++;        p++;      }      bufsize++;      p++;      num--;     }   }   num = bufsize;   /*开始分配内存*/   char* result ;   result = (char*)malloc(sizeof(char)*(bufsize+1));   memset(result,0,sizeof(char)*(bufsize+1));   /*开始复制字符串*/   int i = 0;   int j = 0;   while(num != 0)   {     result[i++] = start_char[j++];     num--;   }   /*尾部置零*/   result[bufsize] = '/0';   return result;}int main(){   /*进行测试*/   char* t = "a哈哈aab和c哈";   printf("length: %d/n",StrLenU("哈哈a哈a哈"));   printf("指向前%s/n指向后:%s/n",t,StrSetPosU(t,3));   printf("全字符时字符个数:%d/n",StrLenMemU(t,6));   printf("半个字符时字符个数:%d/n",StrLenMemU(t,4));    printf("1.正常取值:%s/n",StringSubU("a哈aa哈a",1,2));   printf("2.负值取值:%s/n",StringSubU("a哈aa哈a",-1,2));   printf("3.起始值过大:%s/n",StringSubU("a哈aa哈a",7,2));   printf("4.取值过大:%s/n",StringSubU("a哈aa哈a",5,3));   printf("5.负值取全部:%s/n",StringSubU("a哈aa哈a",4,-1));   return 0;}

  #include <stdio.h>   #include <stdlib.h>   #include <string.h>       void isSymmetrical(char *str)   {     char *begin, *end;     int flag, len = strlen(str);         for (begin = str, end = str + len - 1, flag = 1; begin <= end; begin ++, end --) {       if (*begin != *end) {         flag = 0;         break;       }     }         if (flag)       printf("Yes!/n");     else       printf("No!/n");   }           int main(void)   {     char str[1001];         while (gets(str)) {       isSymmetrical(str);     }         return 0;   }       

  #include <stdio.h>   #include <string.h>   #include <stdlib.h>       /**    * 最长回文字串的长度    */   void maxSymmetricalSubstring(char *str)   {     int maxlength, len;     char *pre, *next, *current;           current = str + 1;     maxlength = 0;         while (*current != '/0') {       pre = current - 1;       next = current + 1;           while (pre >= str && *next != '/0' && *pre == *next) {         pre --;         next ++;         }           len = (next - 1) - (pre + 1) + 1;               if (len > maxlength) {         maxlength = len;       }           pre = current - 1;       next = current;           while (pre >= str && *next != '/0' && *pre == *next) {         pre --;         next ++;       }       len = (next - 1) - (pre + 1) + 1;           if (len > maxlength) {         maxlength = len;       }           current ++;     }           printf("%d/n", maxlength);   }         int main(void)   {     char str[101];         while (gets(str)) {       maxSymmetricalSubstring(str);     }         return 0;   }