The
tdelete(),
tfind(),
tsearch(), and
twalk() functions manage binary search trees based on algorithms T and D from Knuth (6.2.2). The comparison function passed in by the user has the same style of return values as
strcmp(3).
tfind() searches for the datum matched by the argument
key in the binary tree rooted at
rootp, returning a pointer to the datum if it is found and NULL if it is not.
tsearch() is identical to
tfind() except that if no match is found,
key is inserted into the tree and a pointer to it is returned. If
rootp points to a NULL value a new binary search tree is created.
tdelete() deletes a node from the specified binary search tree and returns a pointer to the parent of the node to be deleted. It takes the same arguments as
tfind() and
tsearch(). If the node to be deleted is the root of the binary search tree,
rootp will be adjusted.
twalk() walks the binary search tree rooted in
root and calls the function
action on each node.
Action is called with three arguments: a pointer to the current node, a value from the enum
typedef enum { preorder, postorder, endorder, leaf } VISIT; specifying the traversal type, and a node level (where level zero is the root of the tree).