void insertBefore(int id, char type[], char gender[], int age, int id_exist)
{
	struct Node* new_node = new Node;
	new_node->id = id;
	strcpy_s(new_node->type, type);
	strcpy_s(new_node->gender, gender);
	new_node->age = age;

	// Find node having value2 and next node of it
	struct Node *temp = start;
	while (temp->id != id_exist)
		temp = temp->next;

	struct Node *prev = temp->prev;

	// insert new_node between temp and next.
	temp->prev = new_node;
	new_node->next = temp;
	new_node->prev = temp->prev;
	prev->next = new_node;

	saveBirdsInFile();
}