I've been working very long on this and I can't find a way out. I've created a node struct and a hash struct. Like this:

typedef struct node { char value[45]; struct node* next; }node; typedef struct hash { int count; struct node* head; }hash;

My dictionary consists of an array of 26 hash structs. The array is called alfabet and I've created a global pointer to alfabet (hash *alfabet). Then I mallocced 26 structs for it inside my load function. I have a separate function that returns a node. This node is equal to temp. When I insert nodes in a hash struct I do the following:

if (!alfabet[letter].head) { alfabet[letter].head = temp; alfabet[letter].count = 1; }else { temp -> next = alfabet[letter].head; alfabet[letter].head = temp; alfabet[letter].count++; }

My first question is: is the head now pointing to temp or is it being replaced by temp? Is that causing my problem? I'm using a space reserved for a hash struct and pushing a node inside? This does produce a nice looking hash table but my checker doesn't work. I've made a cursor from a hash struct and from a node struct. Hash works a little bit better. It looks like this:

struct node *cursor = alfabet[teller].head or struct hash *cursor = &alfabet[teller]

But it doesn't work. I try to get to the value of a node like this :

with the node cursor : cursor -> value with the hash cursor : cursor -> head -> value

It does work for a number of words but I run into errors. I get EMs like this.

runtime error: member access within null pointer of type 'struct node' runtime error: null pointer passed as argument 2, which is declared to never be null /usr/include/string.h:145:33: note: nonnull attribute specified here Segmentation fault

It's the same EM whether I use a node or a hash cursor. The EMs always refer to the line in which I strcmp the word from the text with the value in a node. I can't fix it. I've tried and tried and tried. Maybe I could solve this by dereferencing the value properly but I can't figure out how. I hope I've given you sufficient information. Of course I can give you lots more. Thank you.

  • What's the meaning of this hash struct? Does it mean you're attempting a hashmap (which is just an array of linked lists, with the index being derived from some hash)?
    – Blauelf
    Aug 4, 2017 at 14:10
  • Well, I found that hash struct on the internet and somehow I never was able to get rid of it. The head pointer is handy. The index is derived from a hash function that I found in CS50 study. I copied it and it works very well.
    – Karin
    Aug 4, 2017 at 14:17

1 Answer 1


Ok,it's not really a pointer issue. Sometimes my cursor simply equals null. I think I have to review how I read in the text I wish to check. Or my apostrophe function in which I deal with colons, comma's ... I am so sorry for all the fuss, I was very tired and my impostor syndrome played up. When that happens I refuse to stop trying and I end up writing questions like this. I'd delete it because it doesn't really share any relevant information, does it?

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