Binary Search Tree remove node function
I am working on a binary search tree and i have been given an insertnode function that looks like
void insertNode(Node **t, Node *n)
{
if(!(*t))
*t=n;
else if((*t)->key<n->key)insertNode(&(*t)->right,n);
else if((*t)->key>n->key) insertNode(&(*t)->left,n);
}
I am trying to write a function that removes nodes recursively so far i have come up with:
void remove(int huntKey,Node **t)
{
bool keyFound=false;
if(!(*t))
cout<<"There are no nodes"<<endl;
while(keyFound==false)
{
if((*t)->key==huntKey)
{
keyFound=true;
(*t)->key=0;
}
else if((*t)->key < huntKey)remove(huntKey,&(*t)->right);
else if((*t)->key> huntKey) remove(huntKey,&(*t)->left);
}
}
Both of these functions are getting called from a switch in my main function which looks like:
int main()
{
int key=0,countCatch=0;char q;
Node *t, *n;
t=0;
while((q=menu()) !=0)
{
switch(q)
{
case'?': menu(); break;
开发者_StackOverflow社区 case'i': inOrderPrint(t); break;
case'a': preOrderPrint(t); break;
case'b': postOrderPrint(t); break;
case'c': {cout<<"enter key: ";cin>>key;
n=createNode(key);insertNode(&t,n);break;}
case'r':{cout<<"enter the key you want removed: ";
cin>>key;
remove(key,&t);
break;}
case'n': {countCatch=countNodes(t);cout<<countCatch<<"\n"; };break;
}
}
return 0;
}
my remove node function is not working properly....any advice would help....
When you remove the node, you are only setting its key to '0', not actually removing it.
Example: '4' has child '2,' which has children '1' and '3.'
In your code, removing '2' gives you this tree: 4 has child 0, which has children 1 and 3.
To remove an internal node (a node with children), you must handle its parent pointer and its children. You must set the parent's child-pointer to one of the removed node's children. Check this article for more:
http://en.wikipedia.org/wiki/Binary_tree#Deletion
Look at the code, it is not recursive though http://code.google.com/p/cstl/source/browse/src/c_rb.c
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