CODEWITHSUNDEEP
cstruct
JohnDotOwl
JohnDotOwl

Reputation: 3755

Segmentation Error 11 Upon calling Struct Member

Based on my current understanding it's something related to not allocating memory properly.

I don't understand why can it print item->key and not call the compare function? The struct item* item is already in the memory I guess?

Any advice? been stuck for quite awhile

struct item
{
    char* key;
    struct item *left;
    struct item *right;
};


int compare(char* A, char* B){
  return strcmp(A, B);
}

struct item* insert(struct item* item, char* key)
{
    printf ("(%s):",key);

     printf ("(%s)\n",item->key); // I can do Node->Key here

     compare(item->key, key); // I cant do node->key here // Segmentation Error
}

Potential fix? I tried allocating it a memory and loading the item into it. Still the same result too. Just trying anything I can find :(

struct item* item = (struct item*) malloc(sizeof(struct item));

Upvotes: 0

Views: 29

Answers (2)

Mike Nakis
Mike Nakis

Reputation: 62045

After your clarification about what is being printed, the only thing I can guess is that your compiler is trolling you, and the segfault is not really happening in your invocation of compare(item->key, key); but within strcmp().

printf() checks for null arguments, so if item->key is null, then printf() will print "null". On the other hand, strcmp() does not check for null, and it will crash if you pass null to it. A crash on compare() just does not make any sense at all.

Of course it should be noted that compilers are not known to troll people. There must be a better explanation.

Upvotes: 1

timrau
timrau

Reputation: 23058

You did initialize item, but you didn't assign item->key properly. item->key still points to somewhere uninitialized.

Upvotes: 1

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