CODEWITHSUNDEEP
c++
asamolion
asamolion

Reputation: 848

C++ - remove a node from any index in singly linked circular list

I'm writing a circular list class for my college assignment and I need to implement a function that removes the node at the given index from the circular linked list and returns a pointer to that node.

Here is my node class. All functions work fine.

struct Node
{    
    int nData;
    Node* next;

    Node(); // Null Constructor
    Node(int data); // Parameterized Constructor
    Node(Node& newNode); // Copy constructor
    ~Node(); // Destructor
    Node& Print(); // display function
};

And here is my node remove function.

Node* CCircleList::removeAt(int index) // remove node at specified index
{
    if (index < 0)
    {
        index = 0;
    }
    if (index == 0)
    {
        return remove();
    }
    else if (index >= count)
    {
        demoteIndex(); // tail points to it's predecessor
        Node* ptr = tail->next;
        tail->next = ptr->next;
        ptr->next = NULL;
        setPosition(0);
        return ptr;
    }
    else if (index = (count - 1))
    {
        promoteIndex(); // tail points to tail->next
        setPosition(index - 1); // sets Node pointer current to index
        Node* ptr = current->next;
        promoteIndex();
        current->next = ptr->next;
        ptr->next = NULL;
        return ptr;
    }
    else
    {
        setPosition(index - 1);
        Node* ptr = current->next;
        current->next = ptr->next;
        ptr->next = NULL;
        return ptr;
    }
}

count = number of nodes in list.

tail = last node in list.

tail->next = first node in the list.

The function works for all indices except for count-1, Any help would be appreciated. Thanks in advance.

Code of other functions

CCircleList& CCircleList::promoteIndex() // tail points to it's successor
{
    if (!tail) return *this;
    tail = tail->next;
    return *this;
}
CCircleList& CCircleList::demoteIndex() // tail points to it's predecessor
{
    if (!tail) return *this;

    for (int i = 1; i <= count - 1; i++)
    {
        tail = tail->next;
    }

    return *this;
}
CCircleList& CCircleList::setPosition(int index) // set current to specified index
{
    if (index < 0) index = 0;
    if (index >= count) index = count - 1;

    current = tail->next;

    for (int i = 0; i < index; ++i)
    {
        current = current->next;
    }

    return *this;
}

Upvotes: 0

Views: 356

Answers (1)

Walter
Walter

Reputation: 45414

Instead of

else if (index = (count - 1))

try

else if (index == (count - 1))

Upvotes: 1

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