chore(CPlusPlus): add binary search tree (#297)

algorithms/CPlusPlus/README.md

@@ -60,6 +60,7 @@
 2. [Counting and finding sum of all the nodes in BST](Trees/count-and-sum-of-nodes-in-binary-tree.cpp)
 3. [Level Order Traversal](Trees/level-order-traversal.cpp)
 4. [Depth first Traversal](Trees/pre-in-post-traversal.cpp)
+5. [Binary Search Tree](Trees/binary-search-tree.cpp)
 
 # Maths
 1. [Kaprekar Number](Maths/Kaprekar-number.cpp)

algorithms/CPlusPlus/Trees/binary-search-tree.cpp

@@ -0,0 +1,114 @@
+#include <iostream>
+
+//Structure of the Tree
+struct TreeNode{
+	int data;
+	TreeNode* left;
+	TreeNode* right;
+	TreeNode(const int& data): data(data), left(nullptr), right(nullptr){}
+};
+
+TreeNode* find(TreeNode* root, const int& data){
+	/**
+	 * Find the node that contains the given data and
+	 * return that node
+	 *
+	 * @params: `root` root/parent node of the tree
+	 * @params: `data` data to be find in the tree
+	 * @return: tree node that contains the data
+	 *
+	 * Average case Time Complexity: O(log(n))
+	 * Worst case Time Complexity: O(n)
+	 *
+	 */
+
+	if(root == nullptr) 	    { throw std::runtime_error("Error: find() cannot find the data. The data doesn't exist."); }
+	else if(root->data == data) { return root; }
+	else if(root->data < data)  { return find(root->right, data); }
+	else 			    { return find(root->left, data); }
+}
+
+void Insert(TreeNode*& root, const int& data){
+	/**
+	 * Create and Insert the node in the appropriate place of the tree
+	 *
+	 * @params: `root` root/parent node of the tree
+	 * @params: `data` data to be inserted in the tree
+	 * @return: void
+	 *
+	 * Average case Time Complexity: O(log(n))
+	 * Worst case Time Complexity: O(n)
+	 *
+	 */
+
+	if(root == nullptr) 	    { root = new TreeNode(data); }
+	else if(root->data == data) { throw std::runtime_error("The node already exist. Duplicates not allowed"); }
+	else if(root->data < data)  { Insert(root->right, data); }
+	else 			    { Insert(root->left, data); }
+}
+
+void print(TreeNode* root){
+	/**
+	 * Print the tree in an inorder fashion
+	 * 
+	 * @params: `root` root/parent node of the tree
+	 * @return: void
+	 */
+	if(root != nullptr){
+		print(root->left);
+		std::cout << root->data << " ";
+		print(root->right);
+	}	
+}
+
+void free(TreeNode* root){
+	/*
+	 * Free up the memory in the heap
+	 *
+	 * @params: `root` root/parent node of the tree
+	 */
+
+	if(root != nullptr){
+		free(root->left);
+		free(root->right);
+		delete root;
+		root = nullptr;
+	}
+}
+
+int main(){
+	TreeNode* root = nullptr;
+	Insert(root, 37);
+	Insert(root, 19);
+	Insert(root, 4);
+	Insert(root, 2);
+	Insert(root, 11);
+	Insert(root, 22);
+	Insert(root, 20);
+	Insert(root, 51);
+	Insert(root, 55);
+	Insert(root, 42);
+	
+	print(root);
+	/* 
+	Tree structure
+
+		37
+	       /  \
+	      19  51
+	     / \   / \
+	    4  22 42 55
+	   /\	/ 	
+	  2 11  20
+
+	  Output: 2 4 11 19 20 22 37 42 51 55
+
+	*/
+
+	TreeNode* n = find(root, 2);
+	std::cout << "\nValue of n: " << n->data << std::endl; //Output: Value of n: 2
+
+	// free the memory
+	free(root);
+	return 0;
+}