What is the difference between a binary tree data structure and a B-Tree?

A binary tree is a data structure where each node has at most two children (left and right). It is often used to implement binary search trees (BST), where elements are ordered so that the left child is less than the parent, and the right child is greater.

A B-Tree is a balanced tree with multiple keys in each node and a large number of children (more than two). It is optimized for working with large volumes of data on external storage devices (such as disks), minimizing the number of read/write operations. In a B-Tree, each node can contain multiple keys and have many children, which helps maintain balance and high performance during search, insertion, and deletion.

Key differences:

• Number of children: binary tree — maximum 2, B-Tree — many (depends on the order of the tree).
• Balance: B-Tree is always balanced, binary tree can be unbalanced.
• Application: binary trees are more often used in RAM, B-Tree for indexing in databases and file systems.

Example of a simple binary tree in Java:

class Node {
    int key;
    Node left, right;
    Node(int item) {
        key = item;
        left = right = null;
    }
}

A B-Tree is more complex and requires implementation of nodes with arrays of keys and children.