Fixes #29

src/Containers-AVL-Tree-Tests/CTAVLTreeTest.class.st

@@ -334,3 +334,19 @@ CTAVLTreeTest >> testSizeOneElement [
 	tree add: 42.
 	self assert: tree size equals: 1
 ]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testChildParentRelationship [
+	tree add: 50.
+	tree add: 30.
+	tree add: 70.
+
+	self assert: (tree root left parent) equals: tree root.
+	self assert: (tree root right parent) equals: tree root
+]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testRootHasNoParent [
+	tree add: 14.
+	self assert: tree root parent isNil
+]

src/Containers-AVL-Tree/CTAVLAbstractNode.class.st

@@ -15,6 +15,9 @@ Date: October 20, 2023
 Class {
 	#name : 'CTAVLAbstractNode',
 	#superclass : 'Object',
+	#instVars : [
+		'parent'
+	],
 	#category : 'Containers-AVL-Tree',
 	#package : 'Containers-AVL-Tree'
 }
@@ -34,6 +37,11 @@ CTAVLAbstractNode >> children [
 	^ #()
 ]
 
+{ #category : 'accessing' }
+CTAVLAbstractNode >> allChildren [
+	^ #()
+]
+
 { #category : 'enumerating' }
 CTAVLAbstractNode >> childrenDo: aBlock [
 	^ self subclassResponsibility
@@ -72,4 +80,14 @@ CTAVLAbstractNode >> remove: anObject path: list [
 { #category : 'accessing' }
 CTAVLAbstractNode >> withAllChildren: aCollection [ 
 	"Default is to do nothing"
+]
+
+{ #category : 'accessing' }
+CTAVLAbstractNode >> parent [
+	^ parent
+]
+
+{ #category : 'accessing' }
+CTAVLAbstractNode >> parent: aNode [
+	parent := aNode
 ]

src/Containers-AVL-Tree/CTAVLNilNode.class.st

@@ -15,7 +15,7 @@ Class {
 
 { #category : 'adding' }
 CTAVLNilNode >> addChild: newObject [
-	^ CTAVLNode with: newObject
+	^ self parent replace: self with: (CTAVLNode with: newObject)
 ]
 
 { #category : 'private' }
@@ -28,6 +28,11 @@ CTAVLNilNode >> children [
 	^ #()
 ]
 
+{ #category : 'accessing' }
+CTAVLNilNode >> allChildren [
+	^ #()
+]
+
 { #category : 'enumerating' }
 CTAVLNilNode >> childrenDo: aBlock [
 	"Do nothing for nil node"

src/Containers-AVL-Tree/CTAVLNode.class.st

@@ -119,6 +119,17 @@ CTAVLNode >> children [
 	^ { left. right }
 ]
 
+{ #category : 'accessing' }
+CTAVLNode >> allChildren [
+	"Collects all child nodes recursively."
+	| children |
+	children := OrderedCollection new.
+	self left ifNotNil: [children addAll: self left allChildren].
+	self right ifNotNil: [children addAll: self right allChildren].
+	children add: self.
+	^ children.
+]
+
 { #category : 'enumerating' }
 CTAVLNode >> childrenDo: aBlock [
 	left childrenDo: aBlock.
@@ -180,7 +191,8 @@ CTAVLNode >> left [
 
 { #category : 'accessing' }
 CTAVLNode >> left: aNode [ 
-	left := aNode
+	left := aNode.
+	aNode parent: self
 ]
 
 { #category : 'private' }
@@ -261,8 +273,9 @@ CTAVLNode >> right [
 ]
 
 { #category : 'accessing' }
-CTAVLNode >> right: anObject [ 
-	right := anObject
+CTAVLNode >> right: aNode [ 
+	right := aNode.
+	aNode parent: self 
 ]
 
 { #category : 'private' }

src/Containers-AVL-Tree/CTAVLTree.class.st

@@ -98,3 +98,14 @@ CTAVLTree >> search: anInteger [
 CTAVLTree >> size [
 	^ root nodeSize
 ]
+
+{ #category : 'accessing' }
+CTAVLTree >> root [
+	^ root
+]
+
+{ #category : 'accessing' }
+CTAVLTree >> allChildren [
+  "Returns a collection of all child nodes in the tree."
+  ^ root ifNil: [#()] ifNotNil: [root allChildren].
+]