在ubuntu上使用C ++进行分段错误（核心已转储）

Question

I implemented a red black tree but when I run the program from the terminal, it gives the error: Segmentation fault core dumped. I think that I 'm accessing a location that I shouldn't be accessing or I'm accessing something null.

This is my insert method:

template <class Item, class Key>
void RedBlackTree<Item, Key>::Insert(RedBlackTree<Item,Key> Tree, Node<Item, Key> *z)
{
    Node <Item, Key> *T=0;
    Node<Item, Key>* nill=T->nill;
    Node<Item, Key>* root=T->root;
    Node<Item, Key> *y;
    Node<Item, Key> *x;

    y=nill;
    x=root;
    //x= T->getRoot();

    while(x != nill)
    {
        y=x;
         if(z->getKey() < x->getKey())
             x= x->getLeft();
         else
             x = x->getRight();
    }

    z->setParent(y);

    if(y == nill)
        z=T->root;
    else
    if((z->getKey())<(y->getKey()))
    {
        y->setLeft(z);
    }
    else
    {
        y->setRight(z);
    }
        z->setLeft(nill);
        z->setRight(nill);
        z->colour1 = 'R';
        FixingInsert(Tree,z);
}

This is part of my main:

Node<int, int> q = Node<int, int>(0,5);

RedBlackTree<int, int> tree1;


    tree1.Insert(tree1, &q);

Can anyone help please? I am new to templates and I would really appreciate if someone helps me.

Thanks in advance.

Answer 1

You are dereferencing the NULL-pointer (twice!):

Node <Item, Key> *T=0;
Node<Item, Key>* nill=T->nill;
Node<Item, Key>* root=T->root;

I have a feeling you wanted to write:

RedBlackTree <Item, Key> *T= &Tree;
Node<Item, Key>* nill=T->nill;
Node<Item, Key>* root=T->root;

or

RedBlackTree <Item, Key> *T= this;
Node<Item, Key>* nill=T->nill;
Node<Item, Key>* root=T->root;

Although both would be redundant, because you already have the pointer in this (but you can access the member variables directly anyway) and you already have the object Tree whose members you can access via Tree. , too (as long as they are public ).

Also why do you pass a copy of the object to a method of itself? This is completely unnecessary. Even a reference would be redundant.

You probably should remove the Tree parameter, remove the line Node <Item, Key> *T=0; and remove all T-> .