void
*
tdelete(
const void * restrict key
, void ** restrict rootp
, int (*compar) (const void *, const void *)
)
void
*
tfind(
const void *key
const void * const *rootp, int (*compar) (const void *, const void *)
)
void
*
tsearch(
const void *key
, void **rootp
, int (*compar) (const void *, const void *)
)
void
twalk(
const void *root
)void (*action) (const void *, VISIT, int)
),
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).
)
function returns NULL if allocation of a new node fails (usually
due to a lack of free memory).
tfind(),
tsearch(
),
and
tdelete(
)
return NULL if
rootp
is NULL or the datum cannot be found.
The
twalk()
function returns no value.