Question

== 3139 ==条件跳转或移动取决于未初始化的值

== 3139 ==在0x4A0673F：strcpy（mc_replace_strmem.c：311）

== 3139 == by 0x400ADB：htable_insert（hashtable.c：56）

== 3139 == by 0x400F25：main（mylib.c：11）

大家好，我还在尝试插入哈希表。我不能让它工作，我已经包括我的打印方法，只是因为我认为这可能是一个问题。我正在尝试进行线性探测。当我运行valgrind时，我收到了这个错误，我认为它与复制到我的字符串有关，但我不确定是什么意思？我真的不知道如何让这个插入工作，一些输入将是美妙的..
哈希表插入中的第56行是strcpy（str，key）

int htable_insert(htable h, char *str) {
   int i;
   /*convert string to integer*/
   unsigned int index = htable_word_to_int(str);
   /*calculate index to insert into hash table*/
   int remainder = index%h->capacity;
   /*once calculated position in the hash table, 3 possibilities occur*/
   /*no string in this positon, copy string to that position, increment number of keys, return 1*/
   if (h->key[remainder] == NULL) {
      char *key = emalloc(strlen(str) + 1);
      strcpy(str, key);
      h->key[remainder] = key;
      h->frequencies[remainder] = 1;
      h->num_keys++;
      return 1;
   }
   /*the exact same string is at the position, increment frequency at that position, return frequency*/
   if (strcmp(str, h->key[remainder]) == 0) {
      h->frequencies[remainder]++;
      return h->frequencies[remainder];
   }/*a string is at that position, but it isnt the rightone, keep moving along the array
      until you find either an open space or the string you are looking for*/
   if (h->key[remainder] != NULL && strcmp(str, h->key[remainder]) != 0) {
      /*you may need to wrap back around to the beginning of the table, so each time you add
        to the position you should also mod by the table capacity.*/
      for (i = 0; i <= h->capacity; i++) {
         /*no string in this positon, copy string to that position, increment number of keys*/
         if (h->key[remainder] == NULL) {
            char *key = emalloc(strlen(str) + 1);
            strcpy(str, key);
            h->key[remainder] = key;
            h->frequencies[remainder] = 1;
            h->num_keys++;
         }
         /*if you find the string you were looking for, increment the frequecny at the position
           and return the frequency*/
         if (strcmp(str, h->key[remainder]) == 0) {
            h->frequencies[remainder]++;
            return h->frequencies[remainder];
         }
         if (h->key[remainder] != NULL && h->capacity ==  i) {
            i = 0;
         }
      }   
   }
   /*if you have kept looking for an open space but there isnt one, the hash table must fu*/
   return 0;
}

void htable_print(htable h, FILE *stream) {
   int i;
   for(i = 0; i < h->capacity; i++) {
      if(h->key[i] != NULL) {
         fprintf(stream, "%d%s\n", h->frequencies[i], h->key[i]);
      }
   }
}

Answer 1

你的strcpy应该是strcpy（key，str），而不是相反。（你可以使用strdup，btw，并保存malloc + strcpy）。

另外，在： if（h-＆gt; key [remainder]！= NULL＆amp;＆amp; strcmp（str，h-＆gt; key [remainder]）！= 0）{

条件“h-＆gt; key [余数]！= NULL”是多余的：您已经检查过上述情况。

最后，在你的循环中（越过桶），它似乎是：

循环条件应为＆lt;，not＆lt; =
你应该在某处增加余数，或者使用“余数+ i”和索引到h-＆gt;键
而不是“capacity == i” - ＆gt; “i = 0”，只需使用“（余数+ i）％容量”作为h-＆gt;键的索引

..最后终于 - 初始部分，即循环之外的部分，可以在循环中，节省代码。

线性探测哈希表插入

1 个答案: