c++ linked list, removing element disconnects the rest of the list

Question

I was trying to implement this simple linked list project for my homework. When I tried to implement the removeByKey function, I ran into the problem that it disconnects the rest of the list entirely when it finds the key to be removed.

Here's the class:

class LancElem
{
private:
    int key;
    LancElem* next;
public:
    LancElem(){next = nullptr;}
    LancElem(int keyy, LancElem* nextt){key = keyy;next = nextt;}
    LancElem* getNext(){return next;}
    int getKey(){return key;}
    void setNext(LancElem* nextt){next = nextt; }
    void setKey(int keyy){key = keyy;}
};

The remove fucntion:

void removeByKey(LancElem& head, int key){
    LancElem* n = head.getNext();
    while(n->getNext()!=nullptr){
        if(n->getNext()->getKey()==key){
            n->setNext(n->getNext()->getNext());
            delete n->getNext();
            break;
        }
        n=n->getNext();
    }
}

When I try to remove the biggest element:

The original linked list: 4 1 9 8 2 7 3 6 3

Expected output: 4 1 8 2 7 3 6 3

The real output: 4 1 0

The problem is probably where I connect the current element to the next->next element but I can't figure out why my implementation isn't good.

Answer 1

Ask yourself:

What is n->next after the line n->setNext(n->getNext()->getNext()); ? What does the line delete n->getNext(); delete?

You don't want to delete the just updated next but you want to delete the to be removed element:

        auto to_be_deleted = n->getNext(); 
        n->setNext(to_be_deleted->getNext());
        delete to_be_deleted;