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binary_search_tree.cpp
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binary_search_tree.cpp
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/*Project- Binary Search Tree implement all opertions(insertion, searching, deletion, inorder, preorder, postorder, traversing, inorder predecessor and successor,
maximum and minimum value of BST. */
# include <iostream>
# include <cstdlib>
using namespace std;
struct node //node declaration
{
int info;
struct node *left;
struct node *right;
}*r;
class BST
{
public://functions declaration
void search(node *, int);
void find(int, node **, node **);
void insert(node *, node *);
void del(int);
void casea(node *,node *);
void caseb(node *,node *);
void casec(node *,node *);
void preorder(node *);
void inorder(node *);
void postorder(node *);
void show(node *, int);
void findPreSuc(node*, node*&, node*& , int);
int maxValue(node *);
int minValue(node *);
BST()
{
r = NULL;
}
};
void BST::find(int i, node **par, node **loc)//find the position of the item
{
node *ptr, *ptrsave;
if (r == NULL)
{
*loc = NULL;
*par = NULL;
return;
}
if (i == r->info)
{
*loc = r;
*par = NULL;
return;
}
if (i < r->info)
ptr = r->left;
else
ptr = r->right;
ptrsave = r;
while (ptr != NULL)
{
if (i == ptr->info)
{
*loc = ptr;
*par = ptrsave;
return;
}
ptrsave = ptr;
if (i < ptr->info)
ptr = ptr->left;
else
ptr = ptr->right;
}
*loc = NULL;
*par = ptrsave;
}
void BST::search(node *root, int data) //searching
{
int depth = 0;
node *temp = new node;
temp = root;
while(temp != NULL)
{
depth++;
if(temp->info == data)
{
cout<<"\nData found at depth: "<<depth<<endl;
return;
}
else if(temp->info > data)
temp = temp->left;
else
temp = temp->right;
}
cout<<"\n Data not found"<<endl;
return;
}
void BST::insert(node *tree, node *newnode)
{
if (r == NULL)
{
r = new node;
r->info = newnode->info;
r->left= NULL;
r->right= NULL;
cout<<"Root Node is Added"<<endl;
return;
}
if (tree->info == newnode->info)
{
cout<<"Element already in the tree"<<endl;
return;
}
if (tree->info > newnode->info)
{
if (tree->left != NULL)
{
insert(tree->left, newnode);
}
else
{
tree->left= newnode;
(tree->left)->left = NULL;
(tree->left)->right= NULL;
cout<<"Node Added To Left"<<endl;
return;
}
}
else
{
if (tree->right != NULL)
{
insert(tree->right, newnode);
}
else
{
tree->right = newnode;
(tree->right)->left= NULL;
(tree->right)->right = NULL;
cout<<"Node Added To Right"<<endl;
return;
}
}
}
void BST::del(int i)
{
node *par, *loc;
if (r == NULL)
{
cout<<"Tree empty"<<endl;
return;
}
find(i, &par, &loc);
if (loc == NULL)
{
cout<<"Item not present in tree"<<endl;
return;
}
if (loc->left == NULL && loc->right == NULL)
{
casea(par, loc);
cout<<"item deleted"<<endl;
}
if (loc->left!= NULL && loc->right == NULL)
{
caseb(par, loc);
cout<<"item deleted"<<endl;
}
if (loc->left== NULL && loc->right != NULL)
{
caseb(par, loc);
cout<<"item deleted"<<endl;
}
if (loc->left != NULL && loc->right != NULL)
{
casec(par, loc);
cout<<"item deleted"<<endl;
}
free(loc);
}
void BST::casea(node *par, node *loc )
{
if (par == NULL)
{
r= NULL;
}
else
{
if (loc == par->left)
par->left = NULL;
else
par->right = NULL;
}
}
void BST::caseb(node *par, node *loc)
{
node *child;
if (loc->left!= NULL)
child = loc->left;
else
child = loc->right;
if (par == NULL)
{
r = child;
}
else
{
if (loc == par->left)
par->left = child;
else
par->right = child;
}
}
void BST::casec(node *par, node *loc)
{
node *ptr, *ptrsave, *suc, *parsuc;
ptrsave = loc;
ptr = loc->right;
while (ptr->left!= NULL)
{
ptrsave = ptr;
ptr = ptr->left;
}
suc = ptr;
parsuc = ptrsave;
if (suc->left == NULL && suc->right == NULL)
casea(parsuc, suc);
else
caseb(parsuc, suc);
if (par == NULL)
{
r = suc;
}
else
{
if (loc == par->left)
par->left = suc;
else
par->right= suc;
}
suc->left = loc->left;
suc->right= loc->right;
}
void BST::preorder(node *ptr)
{
if (r == NULL)
{
cout<<"Tree is empty"<<endl;
return;
}
if (ptr != NULL)
{
cout<<ptr->info<<" ";
preorder(ptr->left);
preorder(ptr->right);
}
}
void BST::inorder(node *ptr)//inorder traversal
{
if (r == NULL)
{
cout<<"Tree is empty"<<endl;
return;
}
if (ptr != NULL)
{
inorder(ptr->left);
cout<<ptr->info<<" ";
inorder(ptr->right);
}
}
void BST::postorder(node *ptr)//postorder traversal
{
if (r == NULL)
{
cout<<"Tree is empty"<<endl;
return;
}
if (ptr != NULL)
{
postorder(ptr->left);
postorder(ptr->right);
cout<<ptr->info<<" ";
}
}
void BST::show(node *ptr, int level)//print the tree
{
int i;
if (ptr != NULL)
{
show(ptr->right, level+1);
cout<<endl;
if (ptr == r)
cout<<"Root->: ";
else
{
for (i = 0;i < level;i++)
cout<<" ";
}
cout<<ptr->info;
show(ptr->left, level+1);
}
}
void BST::findPreSuc(node* r, node*& pre, node*& suc, int key) //find predecessor and successor
{
if (r == NULL)
return;
// Search for given key in BST.
while (r != NULL) {
// If root is given key.
if (r->info == key) {
// the minimum value in right subtree is successor.
if (r->right) {
suc = r->right;
while (suc->left)
suc = suc->left;
}
// the maximum value in left subtree is predecessor.
if (r->left) {
pre = r->left;
while (pre->right)
pre = pre->right;
}
return;
}
// If key is greater than root, then key lies in right subtree. Root could be predecessor if left subtree of key is null.
else if (r->info < key) {
pre = r;
r = r->right;
}
// If key is smaller than root, then key lies in left subtree. Root could be successor if right subtree of key is null.
else {
suc = r;
r = r->left;
}
}
}
int BST::maxValue(node *node)
{
/* loop down to find the rightmost leaf */
struct node* current = node;
while (current->right != NULL)
current = current->right;
return (current->info);
}
int BST::minValue(node *node)
{
/* loop down to find the rightmost leaf */
struct node* current2 = node;
while (current2->left != NULL)
current2 = current2->left;
return (current2->info);
}
int main()
{
int c, n,item;
BST bst;
node *t;
node *pre = NULL, *suc = NULL;
int key;
while (1)
{
cout<<"-----------------------------------------------------------";
cout<<"\n1.Insert Element "<<endl;
cout<<"2.Delete Element "<<endl;
cout<<"3.Search Element"<<endl;
cout<<"4.Inorder Traversal"<<endl;
cout<<"5.Preorder Traversal"<<endl;
cout<<"6.Postorder Traversal"<<endl;
cout<<"7.Display the tree"<<endl;
cout<<"8.Find in inorder predecessor and successor "<<endl;
cout<<"9.Maximum and Minimum value in BST:"<<endl;
cout<<"10.Quit"<<endl;
cout<<"Enter your choice : ";
cin>>c;
switch(c)
{
case 1:
t = new node;
cout<<"Enter the number to be inserted : ";
cin>>t->info;
bst.insert(r, t);
break;
case 2:
if (r == NULL)
{
cout<<"Tree is empty, nothing to delete"<<endl;
continue;
}
cout<<"Enter the number to be deleted : ";
cin>>n;
bst.del(n);
break;
case 3:
cout<<"Search:"<<endl;
cin>>item;
bst.search(r,item);
break;
case 4:
cout<<"Inorder Traversal of BST:"<<endl;
bst.inorder(r);
cout<<endl;
break;
case 5:
cout<<"Preorder Traversal of BST:"<<endl;
bst.preorder(r);
cout<<endl;
break;
case 6:
cout<<"Postorder Traversal of BST:"<<endl;
bst.postorder(r);
cout<<endl;
break;
case 7:
cout<<"Display BST:"<<endl;
bst.show(r,1);
cout<<endl;
break;
case 8:
cout<<"Enter Key:";
cin>>key;
bst.findPreSuc(r, pre, suc, key);
if (pre != NULL)
cout << "Inorder Predecessor is " << pre->info << endl;
else
cout << "-1";
if (suc != NULL)
cout << "Inorder Successor is " << suc->info;
else
cout << "-1";
cout<<endl;
break;
case 9:
cout << "Maximum value in BST is " << bst.maxValue(r);
cout << "\nMinimum value in BST is " << bst.minValue(r);
cout<<endl;
break;
case 10:
exit(1);
default:
cout<<"Wrong choice"<<endl;
}
}
}