HashTable implementation using BST

BST_Impl_HashTable.cpp

@@ -0,0 +1,176 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <cstdlib>
+using namespace std;
+
+/*
+ * Node Class Declaration
+ */
+template <class T>
+class BSTNode
+{
+    private:
+        T value;
+        BSTNode *left, *right;
+    public:
+        BSTNode(T value) //Constructor
+        {
+            this->value = value;
+            left = NULL;
+            right = NULL;
+        }
+        /*
+         * Adding element to a node
+         */
+        void add(T& value)
+        {
+            if (value < this->value)
+            {
+                if (left)
+                    left->add(value);
+                else
+                    left = new BSTNode(value);
+            }
+            else if (this->value < value)
+            {
+                if (right)
+                    right->add(value);
+                else
+                    right = new BSTNode(value);
+            }
+        }
+        /*
+         * Check if node contains element
+         */
+        bool contains(T& value)
+        {
+            if (value < this->value)
+    	    {
+                if (left)
+            	    return left->contains(value);
+        	else
+           	    return false;
+    	    }
+    	    else if (this->value < value)
+    	    {
+                if (right)
+            	    return right->contains(value);
+        	else
+            	    return false;
+    	    }
+    	    else
+    	    {
+                return true;
+    	    }
+        }
+        friend class BSTHashtable;
+};
+
+/*
+ * Table Class Declaration
+ */
+class BSTHashtable
+{
+    private:
+        int size;
+        vector<BSTNode<string>*>* bucket;
+        int hash(string& s)
+        {
+            unsigned int hashVal = 0;
+            hashVal = s[s.length()-1];
+            return hashVal % size;
+        }
+    public:
+        BSTHashtable(int vectorSize)
+        {
+            size = vectorSize;
+            bucket = new vector<BSTNode<string>*>(size);
+        }
+
+        void add(string& s)
+        {
+            int index = hash(s);
+            if (bucket->at(index) == NULL) //Call friend to add string
+                bucket->at(index) = new BSTNode<string>(s);
+            else
+                bucket->at(index)->add(s);
+        }
+
+        bool contains(string& s)
+        {
+            int index = hash(s);
+            if (bucket->at(index) == NULL)
+                return false;
+
+            if( bucket->at(index)->contains(s)) //Call friend to search the String
+            {
+                cout<<"String \""<<s<<"\" found at index: "<<index<<endl;
+                return true;
+            }
+            else return false;
+        }
+
+        void display()
+        {
+            for (unsigned int i = 0; i < bucket->size(); i++)
+            {
+                cout <<"[" << i << "] -> ";
+                if (bucket->at(i) != NULL)
+                {
+                    BSTNode<string> *node = bucket->at(i);
+                    display_bst(node);
+                }
+                cout << "Null" << endl;
+            }
+        }
+
+        void display_bst(BSTNode<string> *node) // Calling Friend to show List Items using BST LDR Method
+        {
+	    if (node!=NULL)
+            {
+            	display_bst(node->left);
+            	cout << node->value << " -> ";
+            	display_bst(node->right);
+            }
+        }
+};
+
+
+int main()
+{
+    BSTHashtable table(10);
+    string str;
+    int choice;
+    while (1)
+    {
+        cout<<"\t1.Insert element into the table"<<endl;
+        cout<<"\t2.Find element in the table"<<endl;
+        cout<<"\t3.Display Table Chained with Binary Tree"<<endl;
+        cout<<"\t0.Exit"<<endl;
+        cout<<"\tEnter your choice: ";
+        cin>>choice;
+        switch(choice)
+        {
+        case 1:
+            cout<<"Enter String to be inserted: ";
+            cin>>str;
+            table.add(str);
+            break;
+        case 2:
+            cout<<"Enter String to search: ";
+            cin>>str;
+            if (table.contains(str) == 0)
+                cout<<"String \""<<str<<"\" not found in the table"<<endl;
+            break;
+        case 3:
+            cout<<"Displaying Table Chained with Binary Tree: "<<endl;
+            table.display();
+            break;
+        default:
+            cout<<"\nEnter correct option\n";
+            exit(0);
+        }
+    }
+    return 0;
+}