use template class in Binary_Search_Tree.cpp

Author: ashwek

3_Data_Structures/12_Binary_Search_Tree/Binary_Search_Tree.cpp

@@ -16,157 +16,165 @@ left sub-tree, and less than or equal to any key stored in the right sub-tree.
 
 using namespace std;
 
+template<class DataType>
 class Node{
- public:
- Node *parent, *left, *right;
- int value;
-
- Node(Node *Parent = NULL, int Value = 0, Node *Left = NULL, Node *Right = NULL){
- parent = Parent;
- value = Value;
- left = Left;
- right = Right;
- }
+public:
+ Node<DataType> *parent, *left, *right;
+ DataType value;
+
+ Node(Node<DataType> *parent, DataType value,
+ Node<DataType> *left = NULL, Node<DataType> *right = NULL) {
+ this->parent = parent;
+ this->value = value;
+ this->left = left;
+ this->right = right;
+ }
+
 };
 
+template<class DataType>
 class BST{
- private:
- Node *root;
- public:
- BST(){
- root = NULL;
- }
- bool is_empty(){
- return root == NULL;
- }
- void insert(int val){
- if( is_empty() )
- root = new Node(NULL, val);
- else{
- Node *current = root, *parent;
- while( current != NULL ){
- parent = current;
- current = ( val <= current->value ) ? current->left : current->right;
- }
-
- if( val <= parent->value )
- parent->left = new Node(parent, val);
- else
- parent->right = new Node(parent, val);
+private:
+ Node<DataType> *root;
+
+public:
+ BST() {
+ root = NULL;
+ }
+
+ bool is_empty() {
+ return root == NULL;
+ }
+
+ void insert(DataType val) {
+
+ if( is_empty() )
+ root = new Node<DataType>(NULL, val);
+ else {
+ Node<DataType> *current = root, *parent;
+ while( current != NULL ) {
+ parent = current;
+ current = ( val <= current->value ) ? current->left : current->right;
  }
+
+ if( val <= parent->value )
+ parent->left = new Node<DataType>(parent, val);
+ else
+ parent->right = new Node<DataType>(parent, val);
  }
+ }
 
-  void preorder(Node *current = NULL){
-  if( current == NULL ) current = root;
+ void preorder(Node<DataType> *current = NULL){
+ if( current == NULL ) current = root;
 
- // Pre-Order = (Root, Left, Right)
- if(current != NULL){
- cout<<current->value <<", ";
- if( current->left != NULL ) preorder(current->left);
- if( current->right != NULL ) preorder(current->right);
- }
+ // Pre-Order = (Root, Left, Right)
+ if(current != NULL){
+ cout<<current->value <<", ";
+ if( current->left != NULL ) preorder(current->left);
+ if( current->right != NULL ) preorder(current->right);
  }
+ }
 
-  void inorder(Node *current = NULL){
-  if( current == NULL ) current = root;
+ void inorder(Node<DataType> *current = NULL){
+ if( current == NULL ) current = root;
 
- // In-Order = (Left, Root, Right)
- if( current != NULL ){
- if( current->left != NULL ) inorder(current->left);
- cout<<current->value <<", ";
- if( current->right != NULL ) inorder(current->right);
- }
+ // In-Order = (Left, Root, Right)
+ if( current != NULL ){
+ if( current->left != NULL ) inorder(current->left);
+ cout<<current->value <<", ";
+ if( current->right != NULL ) inorder(current->right);
  }
+ }
 
-  void postorder(Node *current = NULL){
-  if( current == NULL ) current = root;
+ void postorder(Node<DataType> *current = NULL){
+ if( current == NULL ) current = root;
 
- // Post-Order = (Left, Right, Root)
- if( current != NULL ){
- if( current->left != NULL ) postorder(current->left);
- if( current->right != NULL ) postorder(current->right);
- cout<<current->value <<", ";
- }
+ // Post-Order = (Left, Right, Root)
+ if( current != NULL ){
+ if( current->left != NULL ) postorder(current->left);
+ if( current->right != NULL ) postorder(current->right);
+ cout<<current->value <<", ";
  }
+ }
 
-  void levelorder(Node *current = NULL){
+ void levelorder(Node<DataType> *current = NULL){
 
- vector<Node*> next_level;
-
- if( current == NULL and root != NULL ){
- next_level.push_back(root);
- }
+ vector<Node<DataType>*> next_level;
 
- while( next_level.size() > 0 ){
- cout <<next_level[0]->value <<", ";
+ if( current == NULL and root != NULL ){
+ next_level.push_back(root);
+ }
 
- if( next_level[0]->left != NULL ){
- next_level.push_back(next_level[0]->left);
- }
- if( next_level[0]->right != NULL ){
- next_level.push_back(next_level[0]->right);
- }
+ while( next_level.size() > 0 ){
+ cout <<next_level[0]->value <<", ";
 
- next_level.erase(next_level.begin());
+ if( next_level[0]->left != NULL ){
+ next_level.push_back(next_level[0]->left);
+ }
+ if( next_level[0]->right != NULL ){
+ next_level.push_back(next_level[0]->right);
  }
+
+ next_level.erase(next_level.begin());
  }
+ }
 
-  Node *search(int find){
-  Node *current = root;
+ Node<DataType> *search(DataType find){
+ Node<DataType> *current = root;
 
-  while( current != NULL and current->value != find )
-  current = (current->value < find) ? current->right : current->left;
+ while( current != NULL and current->value != find )
+ current = (current->value < find) ? current->right : current->left;
 
-  return current;
-  }
+ return current;
+ }
 
-  Node *maximum(Node *current = NULL){
-  if( current == NULL ) current = root;
+ Node<DataType> *maximum(Node<DataType> *current = NULL){
+ if( current == NULL ) current = root;
 
-  while( current != NULL and current->right != NULL ) current = current->right;
+ while( current != NULL and current->right != NULL ) current = current->right;
 
-  return current;
-  }
+ return current;
+ }
 
-  Node *minimum(Node *current = NULL){
-  if( current == NULL ) current = root;
+ Node<DataType> *minimum(Node<DataType> *current = NULL){
+ if( current == NULL ) current = root;
 
-  while( current != NULL and current->left != NULL ) current = current->left;
+ while( current != NULL and current->left != NULL ) current = current->left;
 
-  return current;
-  }
+ return current;
+ }
 
-  Node *successor(Node *current){
+ Node<DataType> *successor(Node<DataType> *current){
 
-  if( current == NULL ) return NULL;
+ if( current == NULL ) return NULL;
 
- if( current->right == NULL ){
- while( current->parent != NULL and current->parent->right == current )
- current = current->parent;
- return current->parent;
- }
- else
- return minimum(current->right);
+ if( current->right == NULL ){
+ while( current->parent != NULL and current->parent->right == current )
+ current = current->parent;
+ return current->parent;
  }
+ else
+ return minimum(current->right);
+ }
 
-  Node *predecessor(Node *current){
+ Node<DataType> *predecessor(Node<DataType> *current){
 
-  if( current == NULL ) return NULL;
+ if( current == NULL ) return NULL;
 
- if( current->left == NULL ){
- while( current->parent != NULL and current->parent->left == current )
- current = current->parent;
- return current->parent;
- }
- else
- return maximum(current->left);
+ if( current->left == NULL ){
+ while( current->parent != NULL and current->parent->left == current )
+ current = current->parent;
+ return current->parent;
  }
+ else
+ return maximum(current->left);
+ }
 };
 
 int main(){
 
  int ins_values[] = {28, 33, 21, 37, 21, 47, 40, 22, 1, 16};
- BST a;
+ BST<int> a;
 
  for(int i=0; i<10; i++)
  a.insert(ins_values[i]);
@@ -181,7 +189,7 @@ int main(){
  a.levelorder();
 
  int search = 33;
- Node *srh = a.search(search);
+ Node<int> *srh = a.search(search);
  if( ! srh )
  cout <<"\n\n" <<search <<" not found in tree";
  else
@@ -190,7 +198,7 @@ int main(){
  cout<<"\n\nMax node = " <<a.maximum()->value;
  cout<<"\nMin node = " <<a.minimum()->value;
 
- Node *temp = a.successor(a.search(22));
+ Node<int> *temp = a.successor(a.search(22));
  if( temp != NULL ) cout<<"\n\nSuccessor of 47 = " <<temp->value;
  temp = a.predecessor(a.search(22));
  if( temp != NULL ) cout<<"\nPredecessor of 47 = " <<temp->value;