double pointer

void insert(Node** curruntNode, char insertChar){
    Node *insertNode = (Node*)malloc(sizeof(Node)), *cur = *curruntNode;
    insertNode -> ch = insertChar;
    insertNode -> next = cur -> next;
    cur -> next = insertNode;
    insertNode -> prev = *curruntNode;
}//correct
void insert(Node** curruntNode, char insertChar){
    Node *insertNode = (Node*)malloc(sizeof(Node));
    insertNode -> ch = insertChar;
    insertNode -> next = *curruntNode -> next;
    *curruntNode -> next = insertNode;
    insertNode -> prev = *curruntNode;
}