B+ Tree in C

B+ Tree is an extension of the B-tree with some specific characteristics that make it particularly useful for database and filesystem implementations.

Nodes in B+ Tree

In B+ tree, all the data is pointed to by the leaf nodes. Internal nodes are only used for the pointing purposes. All the leaf nodes are in the same level.

• Internal Nodes: These contain only keys to guide the search but not actual data values. These keys are used to search for the elements inside the B+ trees. They have pointers to child nodes.
• Leaf Nodes: These contain keys and actual data values. They are linked together to form a linked list, which allows for efficient range queries and ordered traversal.

The number of children a node can have is dependent on the order of the B+ tree.

Order of B+ Tree

The order m of a B+ tree defines the maximum number of children that an internal node can have. An internal node can have at most m children and at least m/2 childrens except the root, which can have fewer.

The root node of the B+ tree must have a minimum of two children and must contain at least one key.

Representation of B+ Tree in C

To represent a node of a B+ tree in C, we will define a structure with the following data members:

typedef struct Node {
    int* keys;
    int t; 
    struct Node** children;
    int n; 
    bool leaf; 
    struct Node* next; 
} Node;

A B+ tree is a self-balancing tree data structure that maintains sorted data and allows searching, inserting, and deletion of data in logarithmic time. In B+ trees, the actual data is stored inside the leaf nodes and the internal nodes act as pointers to the leaf nodes. In this article, we will learn the implementation of a B+ tree in C.