CODEWITHSUNDEEP
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Christian Lindemann
Christian Lindemann

Reputation: 31

What is wrong with my function for counting names in a linked list?

This is part of a larger bit of code but I will include what I think is important. There are actually two types of linked lists I am working with. As you will see the first struct just links to the first node of the list.

Here's the first:

typedef struct mlist {
    Node *headFirstName;
    Node *headLastName;
} MultiLinkedList;

Here's the second:

typedef struct node {
    char *first;
    char *last;
    long number;
    struct node *nextFirst;
    struct node *nextLast;
} Node;

Here is how names and numbers are currently added to the list:

MultiLinkedList *add(MultiLinkedList *list, char *first, char *last, long num) {
    // allocate a new node
    Node *newNode = malloc ( sizeof(Node) );
    newNode->first = malloc ( strlen(first) + 1 );
    strcpy(newNode->first, first);
    newNode->last = malloc ( strlen(last) + 1 );
    strcpy(newNode->last, last);
    newNode->number = num;
    // add this new node at the head of the "byFirst" list
    newNode->nextFirst = list->headFirstName;
    list->headFirstName = newNode;
    // add this new node at the head of the "byLast" list
    newNode->nextLast = list->headLastName;
    list->headLastName = newNode;
    // return the multi-list object with updated head pointers
    return list;
}

And here is how I am currently attempting to count the names in the list:

int size(MultiLinkedList *list) {
    int count = 0;
    Node *newNode = malloc ( sizeof(Node) );
    newNode->nextFirst = list->headFirstName;
    newNode->nextLast = list->headLastName;
    while (newNode->nextFirst!=NULL) {
            count++;

    }
    // return the number of names in the list
    return count;
}

If there is a specific name for traversing multiple lists like this then could someone just direct me to that?

Upvotes: 0

Views: 54

Answers (1)

Stargateur
Stargateur

Reputation: 26747

  • You should use size_t for size
  • Your malloc() is useless
  • If you don't do somewhere something like x = x->next how do you want your loop finish ?
size_t size(MultiLinkedList *list) {
    size_t count = 0;
    for (Node *i = list->headFirstName; i; i = i->next) {
        count++;
    }
    // return the number of names in the list
    return count;
}

Upvotes: 1

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