Method replace_at

Kernel/include/list.h:355–369

	}

	void replace_at(unsigned pos, T obj) {
		assert(num > 0 && pos < num);
		//if (num < 0 || pos >= num) return;
		
		acquireLock(&lock);

		ListNode<T>* current = front;

		for (unsigned int i = 0; i < pos; i++) current = current->next;

		if(current)
			current->obj = obj;
		
		releaseLock(&lock);
	}

	unsigned get_length() {
		return num;