Bubble sort

void sort()
{
    Kafedra * current = head;
    Kafedra* prev = 0;
    Kafedra* tempNode = 0;
    bool changeFlag = false;
    for (int i = 0; i < n; i++)
    {
        while (current->next != 0)
        {
            tempNode = current->next;

            if (current->count_of_students > tempNode->count_of_students)
            {
                changeFlag = true;
                current->next = tempNode->next;
                tempNode->next = current;
                if (prev != 0)
                    prev->next = tempNode;
                prev = tempNode;
                if (head == current)
                    head = tempNode;
                if (current->next == 0)
                    tail = current;
            }
            else
            {
                prev = current;
                current = current->next;
            }
        }
        if (changeFlag == false)
            break;
        else
        {
            prev = 0;
            current = head;
            changeFlag = false;
        }
    }
}