Thread: Array of Linked Lists - Hash table

Hello,
I am trying to write a program that simulates a hash table using chaining to prevent collision. I'm still kind of weak on linked lists so I am having trouble trying to work with an array of linked lists. The problem I am having is that if the index value that the hash function produces is a repetition then i need to add a node to the linked list in that array element. Code compiles but output is incorrect, can anybody tell me what I am doing wrong.
Thanks

Code:

while((fscanf(finp, "%s", string))!= EOF)
    {
      i = hash_function_one (string, size);

      if(curr[i]->string == NULL)
        {
          curr[i] = (list*)malloc(sizeof(list));
          strcpy(curr[i]->string, string);
        }
      if(curr[i]->string != NULL)
        {
          curr[i] = (list*)malloc(sizeof(list));
          strcpy(curr[i]->string, string);
          curr[i]->next = head;
          head = curr[i];
        }
    }

Originally Posted by FortinsM3

Ahh yes, Ok i changed the second if to just an else. The output changed a little but is still incorrect. See anything else?

See my reply in post #2 and if that's that then the next element of the header node points to NULL ie

Code:

if(curr[i]->string == NULL)
{
    curr[i] = (list*)malloc(sizeof(list));
    strcpy(curr[i]->string, string);
    head = curr[i];
    head->next = NULL;
}

Originally Posted by FortinsM3

Ahh yes, Ok i changed the second if to just an else. The output changed a little but is still incorrect. See anything else?

It's not the string its the value produced from hash function, but in that case it just needs to be a single node in that array element. There is only 1 array, each element being LL with 1 or more nodes.
p.s. It does not matter where in the list I add that node, as long as it is in the right list.

Ah! yes I meant that a linked list is started from a new element of that array else you just add another node to the head of an exisiting linked list.

Yes exactly, still nothing though. code looks like this:

Code:

while((fscanf(finp, "%s", string))!= EOF)
    {
      i = hash_function_one (string, size);

      if(curr[i]->string == NULL)
        {
          curr[i] = (list*)malloc(sizeof(list));
          strcpy(curr[i]->string, string);
          head = curr[i];
          head->next = NULL;
        }

      else
        {
          curr[i] = (list*)malloc(sizeof(list));
          strcpy(curr[i]->string, string);
          curr[i]->next = head;
          head = curr[i];

        }

    }

Can you post the part of the code where the array curr[] is defined and the hash func too.