struct ListNode{
    int value;
    struct ListNode* next;
};

void appendNode(struct ListNode* head, int num){
    struct ListNode* nodePtr;
    struct ListNode* newNode;
        newNode = malloc(sizeof(struct ListNode));
    newNode->value = num;
    newNode->next = NULL;

    if(!head)
    head = newNode;
    else{
        nodePtr = head;
        while(nodePtr->next)
            nodePtr = nodePtr->next;
        nodePtr->next = newNode;
    }
}

int main(){
    struct ListNode* head;
    head = NULL;
    appendNode(head, 5);
    printf("%p", head);

return 0;
}